Dendritic Generation Research Articles

Akkermansia muciniphila- and Pathogenic Bacteria-Derived Endotoxins Differently Regulate Human Dendritic Cell Generation and γδ T Lymphocyte Activation.

Lipopolysaccharide (LPS) is a potent endotoxin released at high concentrations in acute infections, causing massive host inflammatory response. Accumulating evidence indicates that dysbiosis-associated chronic low levels of circulating LPS can sustain a prolonged sterile low-grade inflammation that increases the risk of several non-communicable diseases. Interventions aimed at increasing the abundance of beneficial/probiotic bacteria, including Akkermansia muciniphila, result in reduced inflammation, favoring metabolic and immune health. Immunosuppression is a common feature in conditions of chronic inflammation, and dendritic cells (DCs) represent key targets given their ability to shift the balance toward immunity or tolerance. In this study, the effects of low concentrations of LPS from pathogenic (Escherichia coli and Salmonella enterica) and probiotic (Akkermansia muciniphila) bacterial species on human DC generation and functions were compared. We report that monocyte precursor priming with Escherichia coli and Salmonella enterica LPS forces the differentiation of PD-L1-expressing DCs, releasing high levels of IL-6 and IL-10, and impairs their capacity to drive full TCR-Vδ2 T cell activation. Conversely, comparable concentrations of Akkermansia muciniphila promoted the generation of DCs with preserved activating potential and immunostimulatory properties. These results shed light on potential mechanisms underlying the impact of low endotoxemia on disease risk and pathogenesis, and increase our understanding of the immunomodulatory effects of Akkermansia muciniphila.

A PVDF-HFP/YSZ nanofiber composite solid-state electrolyte by in-situ polymerization of 1,3-dioxolane for 4.5 V high-voltage NCM811 battery

Solid lithium metal batteries with solid polymer electrolytes have advantages in terms of high energy density and safety. However, their application is still hindered by unstable solid electrolyte interfaces (SEI and CEI) and uncontrolled dendrite growth. Here, a composite skeleton loaded with dielectric filler yttrium stabilized zirconia nanoparticles (YSZ) on the surface of PVDF-HFP nanofiber filaments is designed, and a novel composite solid electrolyte (CSE) is prepared by in-situ polymerization of DOL (1,3-dioxolane) on this framework to achieve safe and stable high-voltage lithium metal battery (LMB). The dual stable electrode interfaces (CEI and SEI) constructed by in-situ can effectively suppress the generation of lithium dendrites and suppress the degradation of the high-voltage NCM811 positive electrode structure and the generation of cracks in NCM811 particles, endowing the battery with extraordinary performance. The as-obtained CSE exhibits high ionic conductivity of 1.01 × 10−3 S cm−1 at 30 °C, the enlarged electrochemical window of 6.0 V, and the Li+ transference number is 0.72. The assembled Li|NCM811 battery is capable of stable cycling for 400 cycles at a cut-off voltage of 4.5 V and current density of 1C, with a capacity decay of only 0.074 % per cycle. .

Synergy of molybdenum carbide nanosheets with PMIA separator for regulated Li+ transport in high-performance lithium-ion batteries

Separators should not only guarantee the safety performance of lithium-ion batteries (LIBs), but also enable better electrochemical performance, especially in enhancing the power density of LIBs. In this work, Mo2C/PMIA composite separator was prepared by adding molybdenum carbide (Mo2C) nanosheets to m-phenylene isophthalamide (PMIA) via a non-solvent induced phase separation process. The incorporation of Mo2C nanosheets induced a non-homogeneous interfacial modification of the PMIA separator, resulting in the increased porosity of the separator. Furthermore, the electrolyte uptake and its retention were further improved while the Li+ migration resistance was reduced, which manifested into a lower interfacial impedance (73.17 Ω). The Mo2C nanosheets significantly enhanced the adsorption energy of the Mo2C/PMIA composite separator for Li+, which in turn promoted the desolvation effects in the Li-EC of Li+ within the electrolyte and boosted the mobility of Li+. This led to a relatively high ionic conductivity of 0.57 mS cm−1 along with a Li+ mobility number of 0.77. Fast-moving Li+ reduced the concentration polarization of the LIBs, and no polarization was observed after 400 h of cycling with a lithium symmetric battery (Li||Li), suggesting that the generation of lithium dendrites was successfully suppressed using the Mo2C/PMIA composite separator. LiFePO4||Li batteries assembled with the Mo2C/PMIA composite separator demonstrated the ability to retain 90 % of their capacity throughout 150 cycles at a current density of 0.5C, achieving a discharge specific capacity of 128.5mAh g−1, which enables high-performance LIBs.

Highly crystalline nanorods pyrene-based covalent organic framework artificial solid electrolyte interface accelerated interface Li+ regulation on lithium anode

The detrimental effects of heterogeneous Li deposition and aeolotropic Li dendrite propagation critically hamper its serviceability of Li metal batteries. The exploitation of neutral multifunctional porous polymer artificial SEI is imperative to modulate interfacial ionic transfer behavior. Herein, we propose a strategy based on dual-functional nanorod-shaped covalent organic frameworks (COF) to accelerate Li+ diffusion and mitigate lithium dendrite growth by creating an artificial solid electrolyte interface (SEI) layer. As anticipated, the immobilized high-polarity –OH and −CN- groups, along with the porous channel facilitates, facilitate uniform Li+ flux distribution and rapid Li+ migration. Additionally, the highly conjugated nature of the pyrene moiety not only enhances the plane π-π stacking crystallinity of TFDH-COF, but contributes positively to Li+ and repelling TFSI−. The combination of comprehensive ex-situ/in-situ characterizations and DFT calculations have unraveled the underlying mechanisms on the reductive Li mitigation energy barrier and enhancive Li+ transfer ability. In contrast with bare Li, the resultant TFDH-COF@Li electrode demonstrates the elevated reversibility of Li+ utilization, slight polarization, dendrite-free interface and prolonged cyclic performance in Li|Cu, Li|Li, and Li-based full cells operated at rigorous current densities. Those unswerving evidences enlighten the feasibility of engineering the neutrality COF layer to get rid of adverse disordered Li proliferation.

Lithium Dendrite Deflection at Mixed Ionic–Electronic Conducting Interlayers in Solid Electrolytes

AbstractSolid state lithium metal batteries using garnet solid electrolytes such as LLZTO (Li6.4La3Zr1.5Ta0.5O12) promise substantial improvements in energy density and safety. However, practical implementation is hindered by lithium dendrite penetration at high current densities. Recent work shows that internal electrochemically induced mechanical stresses are large enough to propagate lithium dendrites and subsequently fracture solid electrolytes. This study builds on this understanding and demonstrates that stress‐driven dendrite propagation can be controlled via deflection at weakly bonded internal interfaces. This approach, based on a fracture‐mechanics analysis of multilayered composites, is investigated with a variety of interlayer materials that are embedded into LLZTO. The viability and effectiveness of dendrite deflection are most clearly evident with reduced graphene oxide where the critical current density increased from 0.6 to 3.8 mA cm−2. In this material, both the weak interface with LLZTO and the mixed ionic–electronic conducting nature of the interlayer appear to contribute to the improved performance. Additional insight into the mechanics of multilayered electrolytes is also obtained with finite element modeling. The overall results present a promising proof‐of‐concept demonstration along with important generalized design guidelines for creating multilayered solid electrolyte architectures that can enable high‐performance solid‐state batteries.

Interrelations between Dendrite Growth and Electrolyte's Microstructure in Garnet Type Solid Electrolyte

Solid state lithium metal batteries incorporating ceramic solid electrolytes are visioned as a promising alternative for future energy storage. However much has to be investigated regarding the electro-chemo-mechanical stability of these electrolytes. Herein we investigate the role of microstructure of garnet type ceramic solid electrolyte in lithium dendrite propagation. Clear evidence of dendrite favoring the growth along the grain boundaries is observed which suggests the role both mechanical and electronic properties of solid electrolyte plays in dendrite propagation. Furthermore, in our present study, tantalum-doped LLZTO with a nominal composition of Li6.4La3Zr1.4Ta0.6O12 was fabricated using two approaches: one involving conventional powder processing followed by reactive sintering, and the other incorporating an intermediate-stage high-energy milling step. These fabrication routes resulted in distinct microstructures, influencing their electrochemical behavior during extended cycling. The relation between the two was then analyzed in detail using surface science and bulk techniques, as well as quantitative stereology. Notably, our findings demonstrate for the first time that compact grain size distribution critically affects short-circuit failure. Lithium metal dendrites propagate intergranularly along "weak-links" in the microstructure, characterized by percolating arrays of LLZTO grains significantly smaller than the average. Additionally, lithium metal accumulates inside the pores along the dendrite's path through the compact. These observations underscore the role of enhanced electrical conductivity—specifically, electron accumulation—in the dendrite-driven failure phenomenology. Complementing the experimental findings, mechanistic modeling was employed to provide a comprehensive understanding of the interrelations between microstructure, chemo-mechanical stress, and electrochemical stability in garnet-based solid-state electrolytes. Figure 1

Operando Tomographic Imaging of Dendrite Initiation and Propagation in Lithium Metal Solid-State Batteries

The implementation of lithium-anode solid-state batteries (SSBs) faces a significant hurdle in the form of lithium dendrite growth within ceramic solid electrolytes (SEs) during charging at practical rates. Synchrotron X-ray computed tomography (XCT), with its high temporal and spatial resolutions and phase contrast, has emerged as a powerful tool for investigating dendrite-related issues. It offers non-destructive three-dimensional (3D) visualisation of interior structures, including pores and cracks, along with the precise positioning of deposited lithium. Recently, we have established methods and setups for operando tomographic imaging of SSBs, successfully elucidating dendrite initiation and propagation mechanisms1,2. Our findings have demonstrated that dendrite initiation and dendritic crack propagation are separate processes. Initiation occurs as a result of lithium deposition into subsurface pores. Subsequent charging increases pressure within the pores due to slow extrusion of lithium back to the surface, ultimately leading to cracking. Transverse cracks then propagate from the plated electrode to the stripped electrode through wedge opening, with deposited lithium driving the dry crack from the rear. The influences of electrolyte microstructures on dendrite penetration are examined. These understandings hold promise for advancing the development of dendrite-free SSBs through the rational design of SEs. References Z. Ning, et al. Visualizing Plating-Induced Cracking in Lithium-Anode Solid-Electrolyte Cells, Nature Materials, 20, 1121–1129 (2021).Z. Ning, et al. Dendrite Initiation and Propagation in Lithium Metal Solid-State Batteries, Nature, 618, 287–293 (2023).

Understanding and Controlling Stack Pressure Inhomogeneity in Anode-Free Solid-State Batteries

Lithium (Li) metal anodes are widely studied as replacements for current graphite anodes as they have projected higher energy density. However, Li-metal batteries face issues with dendrite propagation and the eventual formation of dead Li. Solid-state batteries (SSBs) are a promising pathway to realize Li-metal batteries, which is attributed to their ability to improve safety and stability through the use of solid-state electrolytes. In particular, “anode-free” SSBs can enable high energy densities by forming a Li metal anode in situ. The initial Li nucleation, plating, and stripping behaviors in anode-free SSBs is influenced not only by the interfacial electrochemistry, but also by the mechanical stresses present along the current collector interface. Mechanical stress also plays a key role in Li metal anode deformation, where creep is the dominant deformation mechanism. However, to date, stack pressure is typically reported as a singular value, rather than considering the temporal and spatial variations in interfacial stress as the battery cycles.This work investigates the role of inhomogeneous stack pressure on Li anode formation and dissolution against a sulfide solid electrolyte. To compensate for this inhomogeneous stack pressure, elastomeric interlayers are used to increase the uniformity of stress along the interface, and thus improve electrochemical cyclability. To analyze the impact of elastomeric interlayers on areal Li plating coverage, post-mortem optical microscopy images of the current collector are captured, showing an improvement in areal coverage from 49% to 70%. The reversible capacity also increases from 89% to 94% with inclusion of an elastomer layer. To confirm the trends in an elastomer layer on increasing stack pressure homogeneity, the mechanical stress at the anode-free interface is modeled using finite-element simulations under different stack pressure geometries. System-level simulations illustrate tradeoffs with respect to the uniformity of mechanical stress and energy density. This work demonstrates the importance of studying external auxiliary components and packaging in SSBs to optimize anode-free SSB performance.

Investigating the Mechanisms of Li Creeping Driven By High Stack Pressure in Sulfide Solid Electrolytes for All-Solid-State Batteries

As the primary use of Li-ion batteries shifts from small electronic devices to electric vehicles, there is a need to increase the stability and energy density of Li-ion batteries. In order to achieve high energy density, use of lithium metal as an anode has being considered due to its high theoretical capacity (3860 mAh g-1) and low reduction potential (-3.04 V vs. SHE). However, the liquid electrolyte used in Li-ion batteries is not only dangerous due to the risk of fire in case of leakage, but also has the disadvantage of shortening the lifetime of the battery due to the generation of lithium dendrites during cycling when lithium metal is used as anode. To overcome these disadvantages, all-solid-state batteries (ASSBs) using solid electrolytes have emerged, which are expected to improve safety and cycling stability even when using lithium metal anodes. Among the various types of solid electrolytes, sulfide solid electrolytes are widely used due to their high ionic conductivity and ductility, which allows easy formation of good interfaces, resulting in high performance ASSBs.ASSBs are suffering from the irreversible capacity loss during cycling results from the contact loss between active material and solid electrolyte particles due to the volume change of active materials during cell cycling.1 Applying high pressure has been suggested as a remedy, reported as either recovering irreversible capacity after applying high pressure to cycled cells or mitigating such losses by applying significant high stack pressure.2,3 However, due to the soft nature of lithium, at high pressure, lithium migrates through the electrolyte layer to the opposite electrode, which is known as Li creep, causing the cell to short-circuit. In order to achieve long life of Li metal ASSBs, it is necessary to understand the Li creep phenomenon induced by high stack pressure.This study endeavors to elucidate the impact of the micro/nano-structure of pore channel in electrolyte layer on the pressure-induced Li creep phenomenon, employing LiI-doped Li3PS4 as the electrolyte due to its stability in contact with Li metal.4 Electrolytes with different particle sizes were prepared and electrolyte pellets were fabricated, and the porosity, pore size and pore channel of the electrolyte pellets were confirmed via micro- and nano-scale X-ray CT. The investigation extends to measuring the time to short-circuit in cells with two different electrolyte pellets under high stack pressure, alongside SEM analysis of the internal structure of the short-circuited cell's electrolyte layer. This analysis aimed to confirm whether lithium migration through the pores is a contributory factor to Li creep, thereby shedding light on the structural factors influencing this phenomenon.

Reactive Sintering of Garnet Type LLZTO from Pyrochlore Synthesized Using a Nonaqueous Sol-Gel Method

Garnet-type solid-state electrolytes such as Li7La3Zr2O12 (LLZO) are promising ceramic electrolytes for all-solid-state batteries because of their high (electro)chemical stability and ionic conductivity. LLZO is typically synthesized from oxide precursors via solid-state reaction, but use of other precursors can lead to improved phase purity and homogenous dopant distribution. We recently demonstrated that pyrochlores synthesized using molten salt synthesis can serve as starting precursor for LLZO, a process we call “pyrochlore-to-garnet” (P2G) [1]. Here, a new, scalable synthesis method for multi-doped pyrochlore is demonstrated using non-aqueous sol-gel methods [2]. The P2G method provides an alternative way to prepare dense LLZO material with greatly reduced sintering time and different microstructure properties compared to other methods. For Ta-doped LLZO (LLZTO), the dense LLZTO ceramic is directly obtained via reactive sintering of the multi-doped pyrochlore with a lithium salt and displays high relative density and ionic conductivity 0.4-0.7 mS/cm, which is comparable to LLZTO prepared by solid-state reaction (SSR), using only 2 hours sintering at 1100 degrees Celsius. Investigation of the synthesis parameters shows that liquid phase sintering is important for achieving high pellet densities and phase-purity in the P2G process. Microstructure analysis also shows that the P2G method results in LLZTO with average grain size of around 3 µm, which is much smaller than the grain sizes (as large as 20 µm) seen in SSR LLZTO. The P2G method also allows for preparation of cubic phase LLZO with other dopants using similar conditions. The P2G method is also applied to prepare other kinds of garnets that display mixed ionic and electronic conductivity, such as Ga and Cr doped Li7Pr3Zr2O12.To better understand the effects of microstructure and grain size on the lithium dendrite propagation behavior, a detailed investigation was carried out on LLZTO prepared with the P2G process and conventional SSR followed by conventional pressureless sintering [3]. Both preparation methods were controlled to keep the phase and elemental composition, ionic and electronic conductivity, relative density, and area specific resistance of the pellets constant. Reflection electron energy loss spectroscopy (REELS) and X-ray photoelectron spectroscopy (XPS) confirmed that both types of LLZTO have similar bandgaps and chemical states. Galvanostatic Li stripping/plating and linear sweep voltammetry measurements show that P2G LLZTO can withstand higher critical current densities (up to 0.4 mA/cm2 in bidirectional cycling and > 1 mA/cm2 for unidirectional) than those seen in SSR LLZTO. Postmortem examination reveals much less Li deposition along the grain boundaries of P2G LLZTO, particularly in the bulk of the pellet, compared to SSR LLZTO after cycling. The improved cycling behavior in P2G LLZTO despite the higher grain boundary area could be from more homogenous current density at the interfaces and different grain boundary properties arising from the liquid-phase, reactive sintering method. This work shows the P2G is a promising and versatile alternate method for the synthesis and processing of many kinds of LLZO materials.

Improvement of Lithium Metal Electrode Performance with Shot Peening and Sputtering By Controlling Stacking Pressure of All Solid State Battery

All-solid-state lithium metal batteries (ASSLiMBs) are expected to load into a next-generation electric vehicle by its high safety and energy density. However, in high current density charging over critical current density (CCD), the lithium dendrite is generated and growth into the solid electrolyte (SE) layer with crack generation and propagation into SE by inhomogeneous deposition, and causing an internal short circuit. It is suggested that if the crack generation and propagation can be suppressed in the SE, the growth of lithium dendrites can be suppressed, and high CCD would be achieved. Some methods have been proposed to suppress dendrite formation.In the author’s research group, shot peening (S.P.) to the SE surface is proposed to increase the CCD by suppressing the crack generation and propagation into the SE with increasing the fracture toughness of the SE [1]. S.P. is a processing method with impacting media onto the target and increase the fracture toughness by mechanical processing. In our previous research, The CCD was successfully increased x7 by the S.P.. The CCD can be increased with combine use of S.P. and conventional sputtering method. By the combination use of these, the CCD was successfully increased x20 [1].The stacking pressure of the ASSLiMB is important operation factor for high CCD, because it controlees the contactivity between Li metal and SE. It is reported that if the stacking pressure is higher than the critical pressure, the lithium dendrite generation is suppressed by high contactivity of Li to SE [2].Synthesizing the findings from above previous research, it can be inferred that ASSLiMB with S.P. sputtering also has a dependency of CCD on stacking pressure. Moreover, the S.P. can change the mechanical characteristics of SE (surface shape, fracture toughness), sputtering can change the interfacial electrochemical resistance. Thus, the influence of stacking pressure on CCD would be different from w/o those processing and it would give us insight for more high performance (high CCD) ASSLiMB. Therefore, in this study, with the aim of improving the performance of the battery, CCD tests under various surface pressures were conducted.Pellets of oxide SE (Li6.25Ga0.25La3Zr2O12) were synthesized via the solid phase reaction method, followed by shot peening using abrasive grain of Al2O3 powder. Subsequently, Au sputtering was processed on the surface of the pellets after shot peening. The experiment carried out to assess the performance of synthesized oxide SE by passing current through it in a lithium symmetric cell sandwiched the SE between lithium metal foils. Subsequently, the acquired data underwent Gaussian regression analysis to predict the true data while accounting for variability by SmartUQ (KEISOKU ENGINEERING SYSTEM CO., LTD.).Fig. 1 shows the pressure dependence of CCD under various processing conditions. In either processing condition, CCD remained consistently low at low pressure, increased as pressure increased at middle pressure, and decreased at high pressure. It became apparent that applying the appropriate pressure during charging and discharging led to an improvement in performance under all processing condition. This is because at low pressure, it is not possible to maintain sufficient contact between SE and Li, while conversely, at high pressure, SE is speculated to be mechanically damaged. At the appropriate pressure, it is presumed that the pressure compresses the surface voids generated by lithium dissolution, thus ensuring consistently good contact. Furthermore, at low pressure, CCD remains unchanged regardless of whether S.P. is performed or not, but CCD changes depending on whether Au sputtering is applied or not. It was found that while performance improvement was observed at all pressure levels with Au sputtering, S.P. resulted in performance enhancement only within a limited range of pressure. This is because Au sputtering improves electrochemical contact, allowing for consistent good contact regardless of pressure. On the other hand, for the roughness imparted by S.P. processing to sufficiently embed, a pressure exceeding the creep pressure of lithium is necessary.This study shows that to improve the performance of ASSLiMBs using S.P. and Au sputtering, it is necessary to apply optimum stacking pressure during charging and discharging.AcknowledgementThis work was partially supported by JSPS KAKENHI Grant Number 22K14761, the Kurata Grants, and JKA foundation. Gaussian regression process analysis conducted by SmartUQ was carried out with the cooperation of KEISOKU ENGINEERING SYSTEM CO., LTD.

Development of High-Capacity Black Phosphorus Carbon Composite Anode Material with Suppressed Dendrite Generation and Its Lithium-Ion Batteries

1, IntroductionFor further implementation of electric vehicles in society, it is essential to further improve the capacity and the fast-charging performance of battery, which are largely dependent on active materials. To improve the energy density and rate characteristics of lithium-ion batteries, it is inevitable to develop new anode materials. As new materials to replace the current graphite anode, alloy-based anode materials such as silicon and metallic lithium have been studied for many years, and some of them are actually used. Although silicon-based materials exhibit high theoretical capacity, there is a trade-off between long life and capacity. Increasing the silicon content improves the energy density, but there is an upper limit to the amount of silicon in the negative electrode because it causes cycle degradation. On the other hand, industrial use of metallic lithium as the ultimate high-capacity negative electrode has been researched and developed for many years, but lithium dendrites remain a major problem, in addition to the large volume change of expansion and contraction during the charge/discharge process.In contrast, phosphorus-based materials have high theoretical capacity (2596mAh/g) and high lithium insertion potential (0.7V vs. Li/Li+), so they are expected to be a high-capacity negative electrode with dendrite suppression. Among them, black phosphorus-carbon composites have been studied in various ways because of their high capacity and high electronic conductivity.[1][2] Although the chemical bonding between phosphorus and carbon is said to be important for high capacity,[3] no material has yet been found that simultaneously satisfies capacity, rate characteristics, and cycle life. Therefore, for the purpose of achieving both of these goals in this study, cup-stacked nanotubes (CSCNTs), which contain many edge structures calculated to be highly reactive with phosphorus,[4] were used for the first time as a model material to prove the hypothesis, and CSCNTs were complexed with black phosphorus to investigate their analytical and electrochemical properties. [5] 2, ExperimentBlack phosphorus (Rasa Industries) and cup-stacked nanotubes (CSCNT, GSI Creos) were mixed and ball milled under inert atmosphere for 12 hours to synthesize black phosphorus carbon composite negative electrode material A. The obtained materials were analyzed by HR-STEM, EELS, XRD, XPS, Raman, TG-DTA, and BET specific surface area. A 2023-type coin cell using lithium metal as the counter electrode was also prepared, and charge/discharge tests were conducted.3, Result and discussionThe synthesized black phosphorus carbon composite anode material A showed a high specific capacity (0.18A/g) of 1642mAh/g (based on the whole anode composite) and a high ICE of 89.3% (Fig.). The rate characteristics of this material A was 1455mAh/g at 9.0A/g and as the cycle performance of it, 90% capacity retention after 200cycles of charge/discharge at 25°C(0.001-2.5V, 3.6A/g) was confirmed.While The BET specific surface area of the raw material CSCNT was >75 m2/g (black phosphorus: <11 m2/g), the composite anode material A was <13 m2/g, showing a significant reduction compared to the initial CSCNT. XRD measurement of material A showed that both black phosphorus and CSCNT peaks disappeared completely and changed to amorphous state, HR-STEM analysis showed that it has a partially layered structure different from the black phosphorus interlayer distance (0.54 nm), and EELS mapping confirmed that the carbon and phosphorus are homogeneously dispersed on the nm order homogeneous dispersion of carbon and phosphorus. As for the bonding state of phosphorus and carbon, peaks suggesting P-O-C bonding were observed in XPS, but XPS and Raman did not convincingly and certainly show if P-C bond exists or not. It is assumed that the high energy density, high rate, and long life are achieved by the nano-dispersion of phosphorus, which contributes to high capacity, through the bonding with carbon which has electronic conductivity.4, ConclusionThe black phosphorus carbon composite anode material using the cup-stacked carbon nanotube (CSCNT) exhibited a high specific capacity of 1642mAh/g (0.18A/g) and an ICE of 89.3%. The rate characteristic of this material was 1455mAh/g at 9.0A/g, and the cycle test at 25°C (0.001-2.5V, 3.6A/g) showed 90% capacity retention. As for the bonding between phosphorus and carbon, a peak suggesting P-O-C bonding was observed by XPS. It is assumed that the phosphorus, which contributes to high capacity, is nano-dispersed by bonding with electron conductive carbon, resulting in high capacity, high rate, and long life.5, Reference[1] H. Jin et al., Science 370,192-197 (2020).[2] R. Amine et al., Nano Energy 74, 1048-49 (2020).[3] J. Sun, et al., Nano Lett. 14, 8, 4573-4850 (2014).[4] S. Zhang et al., ACS Nano 15, 3365-3375 (2021).[5] Y. Ju et al., Electrochemistry 90, 027007 (2022). Figure 1

Dual driven asymmetric electrolyte with gradient distributed UPy-CNTs for high-performance lithium metal batteries

Asymmetric electrolytes with both anode and cathode compatibility are promising candidates for high-energy–density batteries and high-safety lithium metal batteries (LMBs). However, the asymmetric electrolyte is still hindered by the complex multi-layer coating process, resulting in multiple internal interfaces of the electrolyte and poor battery performance. Herein, a one-step constructed asymmetric electrolyte with gradient distributions of 2‐ureido‐4[1H]-pyrimidinone functionalized carbon nanotubes (UPy-CNTs) is prepared via the dual driving forces of solvent evaporation and fluoropolymer migration. On the one hand, during the solvent evaporation process, based on the competitive effect between evaporation of solvent and diffusion of dispersions, the gradient distribution of asymmetric electrolyte can be constructed by enhancing evaporation and inhibiting uniform diffusion. On the other hand, due to the abundant hydrogen bonds between UPy and F, the gradient distribution of UPy-CNTs can be further promoted when the fluoropolymer spontaneously migrates to the surface. The gradient distribution of UPy-CNTs not only greatly increases Young’s modulus of the asymmetric electrolyte on the Li metal side, but also can adjust the Li+ solvation structure to form a LiF-rich solid electrolyte interface (SEI), thereby inhibiting the generation and growth of lithium dendrites. Because of the ingenious structure of the asymmetric electrolyte, the ionic conductivity is 0.226 mS cm−1 and the Li+ transferences number is 0.79. Prominently, Li||Li symmetric batteries can stably cycle for 2500 h at 0.1 mA cm−2 and 0.1 mAh cm−2. In addition, Li||LFP batteries can maintain a high specific capacity of 146 mAh g−1 after 200 cycles at 0.5C.

Multifunctional Nanocomposite Polymer‐integrated Ca‐doped CeO2 Electrolyte for Robust and High‐rate All‐solid‐state Sodium‐ion Batteries

AbstractDue to the seamless interfaces between solid polymer electrolytes (SPEs) and electrode materials, SPEs‐based all‐solid‐state sodium‐ion batteries (ASSSIBs) are considered promising energy storage systems. However, the sluggish Na+ transport and uncontrollable Na dendrite propagation still hinder the practical application of SPEs‐based ASSSIBs. Herein, Ca‐doped CeO2 (Ca−CeO2) nanotube framework is synthesized and integrated with poly (ethylene oxide) methyl ether acrylate‐perfluoropolyether copolymer (PEOA‐PFPE), resulting in multifunctional solid nanocomposite electrolytes (namely SNEs, i.e., PEOA‐PFPE/Ca−CeO2). Our investigations demonstrate that the fluorous effect incurred by the fluorine‐containing PEOA‐PFPE and the oxygen vacancy effect induced by the Ca−CeO2 framework could synergistically promote the dissociation of sodium salt, ultimately enhancing the Na+ mobility in SNEs. Besides, the resultant SNEs construct rapid Na+ transport channels and homogenize the Na deposition in SNEs/Na interface, which effectively prevents the Na dendrite growth. Furthermore, the assembled carbon‐coated sodium vanadium phosphate (NVP@C)||PEOA‐PFPE/Ca−CeO2||Na coin cell delivers impressive rate capability of 97.9 mAh g−1 at 2 C and outstanding cycling stability with capacity retention of 84.3 % after 300 cycles at 1 C. This work illustrates that constructing multifunctional SNEs via incorporating functional inorganic frameworks into fluorine‐containing SPEs could be a promising strategy for the commercialization of robust and high‐performance ASSSIBs.

Multifunctional Nanocomposite Polymer-integrated Ca-doped CeO2 Electrolyte for Robust and High-rate All-solid-state Sodium-ion Batteries.

Due to the seamless interfaces between solid polymer electrolytes (SPEs) and electrode materials, SPEs-based all-solid-state sodium-ion batteries (ASSSIBs) are considered promising energy storage systems. However, the sluggish Na+ transport and uncontrollable Na dendrite propagation still hinder the practical application of SPEs-based ASSSIBs. Herein, Ca-doped CeO2 (Ca-CeO2) nanotube framework is synthesized and integrated with poly (ethylene oxide) methyl ether acrylate-perfluoropolyether copolymer (PEOA-PFPE), resulting in multifunctional solid nanocomposite electrolytes (namely SNEs, i.e., PEOA-PFPE/Ca-CeO2). Our investigations demonstrate that the fluorous effect incurred by the fluorine-containing PEOA-PFPE and the oxygen vacancy effect induced by the Ca-CeO2 framework could synergistically promote the dissociation of sodium salt, ultimately enhancing the Na+ mobility in SNEs. Besides, the resultant SNEs construct rapid Na+ transport channels and homogenize the Na deposition in SNEs/Na interface, which effectively prevents the Na dendrite growth. Furthermore, the assembled carbon-coated sodium vanadium phosphate (NVP@C)||PEOA-PFPE/Ca-CeO2||Na coin cell delivers impressive rate capability of 97.9 mAh g-1 at 2 C and outstanding cycling stability with capacity retention of 84.3 % after 300 cycles at 1 C. This work illustrates that constructing multifunctional SNEs via incorporating functional inorganic frameworks into fluorine-containing SPEs could be a promising strategy for the commercialization of robust and high-performance ASSSIBs.

An anti-freezing hydrogel electrolyte based on hydroxyethyl urea for dendrite-free Zn ion batteries

Aqueous zinc ion batteries are considered as a promising energy storage resource due to their high security, abundant resources and low price. However, the development of aqueous zinc ion batteries has been severely hindered by compulsive dendrite generation, serious side reactions and poor temperature adaptability. Herein, we used hydroxyethyl urea as a hydrogel electrolyte additive to address above-mentioned challenges. Hydroxyethyl urea can break the hydrogen bonds (HBs) of water and enhancing the freezing-tolerance ability of the electrolyte. Meanwhile, hydroxyethyl urea can prevent the corrosion issue and inhibition of Zn dendrites. Consequently, the Zn//Zn symmetric battery can sustain stable cycling for over 3000 h at 1 mA cm−2, and it achieves a high coulombic efficiency of 99.6 %. Even at −40 ℃ the batteries show excellent cycling stability, the Zn//Zn symmetry battery can achieve steadily cycles over 3000 h. The Zn//NVO battery equipped with the altered electrolyte exhibits enhanced capacity retention compared to the one without additives.It demonstrates not only excellent cycling stability at room temperature but also maintains commendable functionality down to −40 ℃, validating the method’s efficacy. This work provides a simple strategy for enhancing low temperature performance of zinc ion batteries.

Synergistic Regulation of Anode and Cathode Interphases via an Alum Electrolyte Additive for High‐Performance Aqueous Zinc‐Vanadium Batteries

AbstractA zinc (Zn) metal anode paired with a vanadium oxide (VOx) cathode is a promising system for aqueous Zn–ion batteries (AZIBs); however, side reactions proliferating on the Zn anode surface and the infinite dissolution of the VOx cathode destabilise the battery system. Here, we introduce a multi‐functional additive into the ZnSO4 (ZS) electrolyte, KAl(SO4)2 (KASO), to synchronise the in situ construction of the protective layer on the surface of the Zn anode and the VOx cathode. Theoretical calculations and synchrotron radiation have verified that the high‐valence Al3+ plays dual roles of competing with Zn2+ for solvation and forming a Zn−Al alloy layer with a homogeneous electric field on the anode surface to mitigate the side reactions and dendrite generation. The Al‐containing cathode–electrolyte interface (CEI) considerably alleviates the irreversible dissolution of the VOx cathode and the accumulation of byproducts. Consequently, the Zn||Zn cell with KASO exhibits an ultra‐long cycle of 6000 h at 2 mA cm−2. Importantly, the VOx cathodes (VO2, V2O5 and NH4V4O10) in the ZS−KASO electrolyte showed excellent cycling stability, including Zn powder||VO2 cells and Zn||VO2 pouch cells. Even better, the full cell exhibits excellent cycling stability at low negative/positive (N/P) ratio of 2.83 and high mass loading (~16 mg cm−2). This study offers a straightforward and practical reference for concurrently addressing challenges at the anode and cathode of AZIBs.

Synergistic Regulation of Anode and Cathode Interphases via an Alum Electrolyte Additive for High-Performance Aqueous Zinc-Vanadium Batteries.

A zinc (Zn) metal anode paired with a vanadium oxide (VOx) cathode is a promising system for aqueous Zn-ion batteries (AZIBs); however, side reactions proliferating on the Zn anode surface and the infinite dissolution of the VOx cathode destabilise the battery system. Here, we introduce a multi-functional additive into the ZnSO4 (ZS) electrolyte, KAl(SO4)2 (KASO), to synchronise the in situ construction of the protective layer on the surface of the Zn anode and the VOx cathode. Theoretical calculations and synchrotron radiation have verified that the high-valence Al3+ plays dual roles of competing with Zn2+ for solvation and forming a Zn-Al alloy layer with a homogeneous electric field on the anode surface to mitigate the side reactions and dendrite generation. The Al-containing cathode-electrolyte interface (CEI) considerably alleviates the irreversible dissolution of the VOx cathode and the accumulation of byproducts. Consequently, the Zn||Zn cell with KASO exhibits an ultra-long cycle of 6000 h at 2 mA cm-2. Importantly, the VOx cathodes (VO2, V2O5 and NH4V4O10) in the ZS-KASO electrolyte showed excellent cycling stability, including Zn powder||VO2 cells and Zn||VO2 pouch cells. Even better, the full cell exhibits excellent cycling stability at low negative/positive (N/P) ratio of 2.83 and high mass loading (~16 mg cm-2). This study offers a straightforward and practical reference for concurrently addressing challenges at the anode and cathode of AZIBs.

Li+ Ion-Dipole Interaction-Enabled a Dynamic Supramolecular Elastomer Interface Layer for Dendrite-Free Lithium Metal Anodes.

The unstable lithium (Li)/electrolyte interface, causing inferior cycling efficiency and unrestrained dendrite growth, has severely hampered the practical deployment of Li metal batteries (LMBs), particularly in carbonate electrolytes. Herein, we present a robust approach capitalizing on a dynamic supramolecular elastomer (DSE) interface layer, which is capable of being reduced with Li metal to spontaneously form strong Li+ ion-dipole interaction, thereby enhancing interfacial stability in carbonate electrolytes. The soft phase in the DSE structure enables fast Li+ transport via loosely coordinated Li+-O interaction, while the hard phase, rich in electronegative lithiophilic sites, drives the generation of fast-ion-conducting solid electrolyte interface components, including Li3N and Li2S. Furthermore, the dynamically resilient DSE network composed of soft and hard phases protects Li anodes from electrolyte corrosion and accommodates volume changes during cycling. All features of the DSE layer synergistically facilitate uniform Li+ deposition and suppress Li dendrite propagation, ensuring a stable and dendrite-free Li anode. Consequently, the symmetric Li||Li cell incorporating the DSE layer achieves cycling stability exceeding 6000 h under 1 mA cm-2 and 1 mA h cm-2 conditions. Furthermore, full cell pairing DSE/Li anode with LiFePO4 (LFP) or high-voltage LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes exhibits high-efficiency Li deposition and cycling stability, even under constrained conditions of limited Li (40 μm) and ultrahigh loading NMC811 cathode (21.5 mg cm-2). This study underscores the effectiveness of the ion-dipole interaction-enabled DSE network in developing stable, high-energy-density LMBs.

Functional organic 7,7,8,8‐tetracyanoquinodimethane artificial layers for the dendrite suppressed lithium metal anodes

AbstractThe large‐scale industrialization of lithium metal (Li), as a potential anode for a high energy density energy storage system, has been hindered by dendrite growth. The construction of an artificial solid electrolyte interphase layer featuring high ionic and low electronic conductivity has been verified to be a high‐performance strategy to confine the dendrite growth and promote the Li anode stability. Therefore, a functional organic protective layer is homogeneously deposited on the Li anode surface via an in situ chemical reaction between tetracyanoquinodimethane (TCNQ) and Li. The as‐synthesized Lin‐TCNQ organic film could efficiently trap non‐uniform Li deposition and restrain dendrite propagation. Particularly, an asymmetric M‐TCNQ‐Li|Cu cell with the Lin‐TCNQ layer breezed through a high Coulombic efficiency of 91.15% after 100 cycles at 1.0 mA cm−2. The M‐TCNQ‐Li|NCM622 cell delivered a high capacity of 143.40 mAh g−1 at 0.2 C and maintained a good cyclic stability of 110.44 mAh g−1 after 160 cycles. The analysis results of spectroscopic tests further demonstrate that the Lin‐TCNQ with the enhanced absorption energy is conducive to lithiophilicity and decreases the overpotential of Li deposition.