Battery Cycling Research Articles

Polymeric Ionic Liquid-Enabled In Situ Protection of Li Anodes for High-Performance Li-O2 Batteries.

Redox mediators (RMs) have shown promise in enhancing Li-O2 battery cycling stability by reducing overpotential. However, their application is hindered by the shuttle effect, leading to RM loss and Li anode corrosion. Here, we introduce a polyionic liquid, poly (1-Butyl-3-vinylimidazolium bis(trifluoromethanesulfonylimine)) ([PBVIm]- TFSI) as an additive, showcasing a novel Li anode protection strategy for LiI-mediated Li-O2 batteries. [PBVIm]+ cations migrate to the Li anode, forming a protective cationic shield that promotes uniform Li+ deposition. The addition of [PBVIm]-TFSI enhances the cycling stability, achieving 105 cycles at 200 mA·g-1, compared to the cell with LiI which exhibited 38 cycles under the same conditions. Synchrotron X-ray tomography reveals the evolution of this protective layer, providing insights into its formation mechanism, in conjunction with XPS analysis. Our findings offer a new approach to Li anode protection in Li-O2 batteries, emphasizing the critical role of interfacial engineering for battery performance.

Mitigating Mechanical Stress by the Hierarchical Crystalline Domain for High-Energy P2/O3 Biphasic Cathode Materials.

Sodium-ion batteries (SIBs) have captured widespread attention for grid-scale energy storage owing to the wide distribution and low cost of sodium resources. Delivery of high energy density with stable retention remains a challenge in developing cathode candidates for rechargeable SIBs. Inspired by the concept of "cationic potential", here, we present a hierarchical crystalline domain in hexagonal particles with target chemical composition (Na0.8Li0.03Mg0.05Ni0.28Fe0.05Mn0.54Ti0.05O2) from the inner bulk O3 phase (71.1 wt %) to the outer P2-type shell (28.9 wt %) of the structure. Benefiting from the mitigated mechanical stress of the predominant bulk O3 phase under the protection of the surficial P2 crystalline domain at the microscale during Na+ (de)intercalation, the brittle fracture, plastic yielding, and structural damage of the bulk O3 phase are effectively prohibited during battery cycling, thereby achieving good structural integrity. As a consequence, the biphasic P2/O3-Na0.8Li0.03Mg0.05Ni0.28Fe0.05Mn0.54Ti0.05O2 material exhibits satisfactory electrochemical properties, with a high energy density of 506 Wh kg-1 and good capacity retention of 85.5% over 200 cycles. This work highlights the importance of tailoring the crystalline domain to mitigate the reaction-induced stress and particle fracture of layered biphasic cathode materials for high-energy SIBs.

Magnesium Fluoride Interlayers Enabled by Wet‐Chemical Process for High‐Performance Solid‐State Batteries

AbstractGarnet‐type solid‐state electrolytes (SSEs) exemplified by Li6.5La3Zr1.5Ta0.5O12 (LLZT) are chemically unstable when exposed to air, leading to the formation of impurities and poor wettability with Li metal. Herein, a protocol to address this Li/LLZT interface challenge is demonstrated by constructing a lithiophilic MgF2 nanofilm on the LLZT pellet. Specifically, a solution‐based process is developed for the surface engineering of LLZT, utilizing magnesium trifluoroacetate (MTF) as the molecular precursor while poly(acrylic acid) (PAA) as the coordinating agent in a sol‐gel process. It is demonstrated that a facile spin‐coating treatment followed by high‐temperature annealing reliably forms crack‐free MgF2 nanofilms with precise thickness control. Introduction an MgF2 interlayer transforms the LLZT pellet into a highly lithophilic, facilitating close contact with the lithium anode, thereby leading to a significantly reduced interfacial resistance from 1190 Ω cm2 to 6 Ω cm2. Such an interfacial engineering enables stable cycling of full batteries with high reversibility and rate capability using commercial LiFePO4 and LiNi0.83Co0.07Mn0.1O2 as cathodes. This study unfolds the possibility of a solution‐based method as a facile and scalable process for the construction of fluoride nanofilms, which is promising to address the critical interfacial challenges of solid‐state batteries (SSBs) to facilitate its practical applications.

Nanotech‐Enhanced Chemical Energy Storage with DNA

AbstractDNA nanotechnology has revolutionized materials science by harnessing DNA's programmable properties. DNA serves as a versatile biotemplate, facilitating the creation of novel materials such as electrode materials and DNA hydrogels for electrolytes and membranes. These advancements have significantly boosted the performance of energy storage devices. DNA biotemplates not only enhance supercapacitor capacitance and increase Li–S battery cycling stability but also improve metal ion transport in perovskite solar cells, enhancing power conversion efficiency. Additionally, DNA's addressable nature allows precise enzyme positioning in biofuel cells, enhancing enzyme cascade efficiency. Overall, DNA nanotechnology offers a potent strategy for enhancing electrochemical device performance and stability through structural engineering.

Progress of silicon and graphene composites in lithium-ion battery anodes

As society progresses, the need for high-power, long-life energy supply devices gradually increases. Lithium-ion batteries (LIBs) with large energy reserves and high power have recently become the preferred choice. The anode of LIBs plays a crucial role in battery performance, safety, and cycle life. Typically, graphite materials are used for LIBs anodes. Still, they have drawbacks such as low first-time Coulombic efficiency, capacity degradation, safety issues, short cycle life, insufficient gram capacity, and purity and side reactions, which limit the application of LIBs. Therefore, new harmful electrode materials are in demand. Graphene and silicon are both environmentally friendly and sustainable materials. They both have the advantages of high theoretical capacity and high energy density, which are critical materials for developing LIBs. Combining the two can exert a synergistic effect and jointly improve the cycle stability of the battery. In this paper, we review the preparation methods of graphene and silicon composites in recent years, including mechanical ball milling and hydrothermal and thermal reduction methods. In addition, graphene and silicon composites have been explored for LIBs applications.

Nanotechnology in Lithium-Sulfur Batteries: Addressing the Challenges in Battery Cycle Life and Safety

Lithium-sulfur (Li-S) batteries, with their high energy density and affordable material prices, are a viable alternative to ordinary lithium-ion batteries, especially for electric cars. Their actual application is limited by challenges such as substantial volume expansion, low electrical conductivity, and the polysulfide shuttle effect, despite their advantages. This research investigates how incorporating nanomaterials into Li-S battery cathodes, anodes, and electrolytes might improve battery performance and analyzes the potential of nanotechnology to address these problems. The application of metal oxides, graphene oxide, and carbon nanofibers to improve the stability and conductivity of sulfur cathodes is covered. Additionally, it examines anode protection strategies using nanocoating and protective layers to inhibit dendrite growth and improve safety. The incorporation of nanoparticles in electrolytes to improve ionic conductivity and reduce side reactions is also analyzed. Despite the progress, challenges such as the polysulfide shuttle effect and volume changes remain. The paper concludes with recommendations for future research to develop commercially viable Li-S batteries with higher capacity, longer lifespan, and improved safety.

Selective ion transport through hydrated micropores in polymer membranes.

Ion-conducting polymer membranes are essential in manyseparation processes and electrochemical devices, including electrodialysis1, redox flow batteries2, fuel cells3 and electrolysers4,5. Controlling ion transport and selectivity in these membranes largely hinges on the manipulation of pore size. Although membrane pore structures can be designed in the dry state6, they are redefined upon hydration owing to swelling in electrolyte solutions. Strategies to control pore hydration and a deeper understanding of pore structure evolution are vital for accurate pore size tuning. Here we report polymer membranes containing pendant groups of varying hydrophobicity, strategically positioned near charged groups to regulate theirhydration capacity and pore swelling. Modulation of thehydrated micropore size (less thantwo nanometres) enables direct control over water and ion transport across broad length scales, as quantified by spectroscopic and computational methods. Ion selectivity improves in hydration-restrained pores created by more hydrophobic pendant groups. These highly interconnected ion transport channels, with tuned pore gate sizes, show higher ionic conductivity and orders-of-magnitude lower permeation rates of redox-active species compared with conventional membranes, enabling stable cycling of energy-dense aqueous organic redox flow batteries. This pore size tailoringapproach provides a promising avenue to membranes with precisely controlled ionic and molecular transportfunctions.

The Mechanism of Aluminum Deposition and Dendrite Growth on a Copper Substrate in Anode-Free Aluminum Batteries.

Given the critical demand for batteries with a high energy density and the global scarcity of lithium, anode-free aluminum batteries (AFABs) have attracted significant attention. AFABs utilize collectors instead of traditional anode metal foils, eliminating the need for anode materials and significantly enhancing the energy density of the batteries. However, the proliferation of aluminum dendrites might cause safety risks and reduce Coulombic efficiency, possibly impeding commercialization. This study employs molecular dynamics (MD) simulations to explore the deposition mechanisms of aluminum (Al) on copper (Cu) collectors and the dynamics of aluminum dendrite growth under nonhomogeneous deposition conditions. The results indicate that the surface properties of the Cu substrate significantly affect aluminum deposition, leading to more homogeneous and amorphous deposition on Cu(110) surfaces. However, the FCC structure of Al atoms on the Cu(111) surfaces exhibited the largest number. Strategically increasing the temperature and pressure can effectively prevent the formation of aluminum dendrites. The results are helpful for enhancing the battery cycle stability and the application of novel AFABs.

Additive effect of Li on electrical property of ZnO passivation layer to control dendritic growth of Zn during recharge processes

This study investigates the effect of Li+ on the dendritic growth of Zn anodes in the presence of a ZnO passivation layer formed after discharge, with particular attention to the initial recharge process. 0.1 mol dm−3 Li+ effectively suppresses dendrites, while 2 mol dm−3 Li+ addition facilitates the same. The difference in Zn dendrite formation behavior is also indicated by the attenuation tendency of the potential oscillation accompanied by hydrogen evolution reaction during recharge. This is attributed to Li+ concentration dependence of the properties of the ZnO passivation layer formed during Zn anode discharge. Li+ modulates the carrier density of ZnO by altering its crystalline defect characteristics; the carrier density of ZnO with 0.1 mol dm−3 Li+ addition becomes approximately three times as high as that without additive owing to the oxygen vacancies and interstitial zinc that form additional donor level. By contrast, 2 mol dm−3 Li+ reduces the carrier density of ZnO by inducing zinc vacancies to form acceptor levels. The highly conductive ZnO produced by adding 0.1 mol dm−3 Li+ improves the reaction uniformity during recharge, which suppresses dendrite formation. This study provides valuable insight into the mechanisms and control strategies of Zn dendrite growth during the charge-discharge cycling of alkaline Zn rechargeable batteries.

Modeling and Simulation of Thermal Effects on Electrical Behavior in Lithium-Ion Cells

Thermal effects exert a crucial influence on the electrical behavior of lithium-ion batteries, significantly impacting key parameters such as the open circuit voltage curve, internal impedance, and cell degradation rate. Furthermore, these effects may give rise to electrolyte loss, resulting in a reduction in capacity. The cycling of batteries inherently generates internal heat, establishing a direct relationship between cell temperature and power demand. This article aims to provide a methodology to model electrothermal relations and temperature influence on electrical behavior in lithium-ion cells, as well as a simulation of extended cell operation under arbitrary power loads, presenting a novel approach not previously explored. It does this by considering three models: the Bernardi model for heat generation within the cell, a thermal lumped model for the cell’s temperature, and the Vogel-Fulcher-Tammann model for the capacity change as a function of temperature. These models are then connected to a state-of-the-art open circuit voltage model of a cell, providing a connection from the thermal world back into the electrical world. Experiments with different power demands occur on the simulation, including estimation of thermal parameters with relative errors under 1%, visualizing the effects of the integrated models and potential for real-cell applications.

Strong Ion‐Dipole Interactions for Stable Zinc‐Ion Batteries with Wide Temperature Range

AbstractAqueous zinc‐ion batteries are widely recognized as promising alternatives to lithium batteries due to their excellent safety, environmental compatibility, and cost‐effectiveness. Nonetheless, the formation of dendrites, corrosion, and undesirable side reactions on the zinc surface pose significant challenges to the cycling stability of zinc‐ion batteries. In this study, polar propylene carbonate (PC) is paired with tetrafluoroborate anions to establish a strong ion‐dipole interaction. Strong ion‐dipole interaction can not only alter the solvation structure of zinc ions but also facilitate the formation of a dynamic double electric layer on the surface of the zinc electrode, suppressing the formation of ZnF2 interface and carbonate, thereby facilitating uniform zinc ion deposition, and consequently improving battery cycling stability over a broad temperature range. Concretely, the formulated electrolyte enhances the cycling stability of the battery over a wide temperature range of −30 to 40 °C, accompanied by a capacity retention of ≈100% even after 10 000 cycles at −30 °C. The symmetrical battery utilizing this electrolyte exhibits stable cycling performance for over 1200 h at 25 °C and 1900 h at −30 °C, respectively. The findings provide a promising direction for the development of long‐cycle batteries capable of operating over a wide temperature range.

1T′-MoSP monolayer as an anode material for sodium-ion batteries with ultrahigh storage capacity and ultralow diffusion barrier

Sodium-ion batteries (SIBs) have gained significant attention due to the abundant availability and low cost of sodium. However, the search for high-performance anode materials remains a critical challenge in advancing SIB technology. Based on first-principles swarm-intelligence structure calculations, we propose a metallic 1T′-MoSP monolayer as an anode material that offers a remarkably high storage capacity of 1011 mA h g−1, an ultralow barrier energy of 0.04 eV, and an optimal open-circuit voltage of 0.29 V, ensuring high rate performance and safety. Additionally, the monolayer presents favorable wettability with commonly used SIB electrolytes. Even after adsorbing three-layer Na atoms, the 1T′-MoSP monolayer retains its metallic nature, ensuring excellent electrical conductivity during the battery cycle. These desirable properties make the 1T′-MoSP monolayer a promising anode material for SIBs.

Sulfide/Polymer Composite Solid‐State Electrolytes for All‐Solid‐State Lithium Batteries

AbstractThis review introduces solid electrolytes based on sulfide/polymer composites which are used in all‐solid‐state lithium batteries, describing the use of polymers as plasticizer, the lithium‐ion conductive channel, the preparation methods of solid‐state electrolytes (SSEs), including dry methods and wet methods with their advantages and disadvantages. In addition, the physicochemical stability of sulfide/polymer composite based solid‐state electrolytes is analyzed. The sulfide/polymer composite based solid‐state electrolyte can be utilized in lithium metal or lithium sulfur batteries. However, there are still many problems left to be solved in practical applications of these solid‐state electrolytes. In this review, several solutions are explored. Firstly, the ultra‐long life cycle of batteries can be achieved by thinning the composite electrolyte. Secondly, when sulfur is applied as the positive electrode, the thinning electrolyte can reduce polarization and other problems. Finally, an integrated battery is employed to reduce the interface impedance. By addressing these aspects, the review aims to provide valuable insights into the future development of high‐performance solid‐state electrolytes in lithium battery technology.

Novel electriferous charge-mosaic S(TMC@Lys-Li) separator towards efficient Li+ fast-transfer for high-energy density and long-duration lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries with attractive capacity give remarkable potential for prospective high-capacity application scenarios but suffer a fatal flaw of short cyclability before large-scale commercialization especially owing to polysulfide (Li2Sn) transmembrane shuttling. To efficiently restrain chronic Li2Sn shuttle and expedite Li+ transfer, herein, a novel electriferous charge-mosaic S(TMC@Lys-Li) separator preparation approach is recommended. Interfacial polymerizations of lithiated lysine and trimesoyl chloride establish an electriferous charge-mosaic polyamide functional layer. Substituted Li within the charge-mosaic layer offers transition or replacement sites for smoothing Li+ migrations, which constructs efficient Li+ fast-transfer private channels and accelerates the Li+ transfer rate to 9.4 times. Negatively charged polyamide skeleton synchronously heightens Li2Sn rejections by combining Donnan and steric effects. S(TMC@Lys-Li) replenishes Li for homogenizing Li nucleation and growth, endowing stable plating/stripping behaviors over 250 cycles for Li-Cu batteries. Assembled Li-S cells thus exhibit excellent specific capacity and cyclability at multiple application scenarios such as long periods, high areal capacity, and fast charge, holding 78.1% retention after 500 cycles at 1 C. The superior thermal stability and self-discharge of S(TMC@Lys-Li) dramatically strengthen battery thermal runaway resistance even at 155 ℃, which ensures security for Li-S battery high-power and high-temperature operations. Above alluring features enable charge-mosaic separators to be potentially adopted in practical Li-S batteries demanding strict security, high-capacity density, and fast charge technology.

Ternary-salt localized high-concentration electrolyte: An ideal companion facilitating stable high-voltage cycling of lithium metal batteries

The strategic design of novel electrolytes to further enhance the overall performance of lithium metal batteries (LMBs) is highly desirable. Herein, combining the synergistic effect of multiple functional lithium (Li) salts and the solvation structure advantage of localized high-concentration electrolyte (LHCE), we propose a novel ternary-salt localized high-concentration electrolyte (TSLHCE) termed CETHER3-TDE that achieves broad electrochemical stability window, dendrite-free Li deposition, effective electrode interface protection, flame retardancy, and significantly enhances the cycling performance of LMBs. CETHER3-TDE enables Li (50 μm thickness) ||NMC622 (13.8 mg cm−2, 2.50 mAh cm−2) cell to achieve an impressive capacity retention of 83 % after 300 cycles with a cut-off voltage of 4.4 V. Additionally, it enables the Li (50 μm thickness) ||NMC811 (19.8 mg cm−2, 3.96 mAh cm−2) cell to achieve a capacity retention of 83.6 % after 170 cycles, under an ultrahigh cut-off voltage of 4.6 V. Furthermore, the Li metal pouch cell employing CETHER3-TDE, featuring a low negative/positive (N/P) capacity ratio of 1.33 and lean electrolytes of 2.3gAh−1, attains an energy density of 413 Wh kg−1 and maintains stable cycling at 4.6 V. Moreover, analysis conducted by Accelerating Rate Calorimeter has verified that CETHER3-TDE enhances both the thermal stability as well as the thermal runaway trigger temperature of LMBs, thereby substantially improving their safety. This work provides valuable insights for future research on multi-salt complex electrolyte system for practical application in high-energy-density and high safety LMBs.

Application and research of three-dimensional composite fiber interlayer in lithium-sulfur battery

Lithium-sulfur (Li-S) batteries are regarded to be the most probable‌ electrochemical energy storage devices for large-scale applications because of their high energy and green characteristics. Nevertheless, the polysulfides generated during the cycle of Li-S batteries can cause the "shuttle effect", reducing the utilization rate of sulfur (S) and electrochemical performance. In this study, a novel three-dimensional composite fiber (TDCF) interlayer was prepared and placed between the S cathode and the PP separator to adsorb polysulfide and restrain the "shuttle effect". The results show that the capacity retention rate of Li-S battery is still higher 3:50 ratio, 200ml of anhydrous ethanol was added to moisten, than 70% after 200 charge-discharge cycles at 1C.

Electronic structure modulation of yttrium sites with heteroanions coordination enhances the bidirectional catalytic performance of lithium-sulfur batteries

Oxyfluorides exhibit unique properties, including catalytic activity and electrical conductivity. However, to date, there has been minimal application of oxyfluorides in the field of lithium-sulfur (Li-S) batteries. This study synthesizes yttrium oxyfluoride-doped semi-encapsulated porous carbon nanofibers (YOF@PCNFs) using through electrospinning strategy for the separator coating in Li-S batteries. The precisely engineered OF heteroanionic environment surrounding the Y cation can adjust the lattice spacing and electronic density of the catalyst. This enhancement improves interactions between the active sites and the reactants, intermediates, and products, reduces the energy barrier for polysulfide (LiPSs) conversion, and enhances the bidirectional catalytic conversion capability of LiPSs. Furthermore, the semi-encapsulated structure helps inhibit polysulfide shuttle and ensures uniform Li-ion deposition. Improved catalysts and the interconnected special structure can establish a series of polysulfides conversion factories which operate efficiently over the long term through a “confinement-adsorption-catalysis-desorption” process, thereby enhancing battery cycling stability. The assembled Li-S full cell exhibits a high initial capacity of 1013.2 mAh/g at 1 mA cm−2 and maintains steady operation over 1500 cycles, with a minimal capacity decay rate of only 0.039 % per cycle. Even at a high current density of 4 mA cm−2, it operates for 200 cycles with an exceptionally low decay rate of 0.081 % per cycle. The study provides an anion hybrid strategy for typical metal catalysts, offering design guidelines for tailored advanced Li-S catalysts.

Preparation of Hierarchical Porous ZIF-67 and Its Application in Zinc Battery Separator

This study successfully prepared a hierarchically porous ZIF-67 (H-ZIF-67) by incorporating the polyvinylpyrrolidone (PVP) at room temperature. Compared to standard control ZIF-67 (C-ZIF-67) with a yield of 81% and a BET specific surface area of 1228 m2·g−1, the H-ZIF-67 not only exhibited improved crystallinity and pore structure but also achieved a yield of up to 93% and a BET specific surface area of 1457 m2·g−1. Due to its hierarchically porous structure, H-ZIF-67 demonstrated excellent adsorption capacity and efficiency for methylene orange (MO). Additionally, the composite separator created by combining H-ZIF-67 with nanocellulose (CNF) exhibited remarkable uniformity and dispersion in zinc batteries. In comparison to a conventional CNF separator, the porous structure and high specific surface area of H-ZIF-67 significantly enhanced its electrolyte wettability and Zn2+ transport rates. Its abundant Lewis acid sites effectively promoted the uniform deposition of Zn2+, thereby suppressing the formation of zinc dendrites and improving the cycling and safety performance of zinc-ion batteries. Experimental results indicate that the ion conductivity of the membrane was 4.31 mS·cm−1, the electrolyte absorption rate was 316%, and it could cycle stable for over 4000 h at a current density of 1 mA·cm−2 with a discharge capacity of 1 mAh·cm−2. This achievement will open up new avenues for the preparation and application of ZIF-67 composite separators in aqueous zinc-ion batteries.

A Quasi-Solid-State Polymer Lithium-Metal Battery with Minimal Excess Lithium, Ultrathin Separator, and High-Mass Loading NMC811 Cathode.

Solid-state batteries with lithium metal anodes are considered the next major technology leap with respect to today's lithium-ion batteries, as they promise a significant increase in energy density. Expectations for solid-state batteries from the automotive and aviation sectors are high, but their implementation in industrial production remains challenging. Here, we report a solid-state lithium-metal battery enabled by a polymer electrolyte consisting of a poly(DMADAFSI) cationic polymer and LiFSI in Pyr13FSI as plasticizer. The polymer electrolyte is infiltrated and solidified in the pores of a commercial LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode with up to 2.8 mAh cm-2 nominal areal capacity and in the pores of a 25 μm thin commercial polypropylene separator. Cathode and separator are finally laminated into a cell in combination with a commercial 20 μm thin lithium metal anode. Our demonstration of a solid-state polymer battery cycling at full nominal capacity employing exclusively commercially available components available at industrial scale represents a critical step forward toward the commercialization of a competitive all-solid-state battery technology.

Design Lithium Exchanged Zeolite Based Multifunctional Electrode Additive for Ultra‐High Loading Electrode Toward High Energy Density Lithium Metal Battery

AbstractThe practicalization of a high energy density battery requires the electrode to achieve decent performance under ultra‐high active material loading. However, as the electrode thickness increases, there is a notable restriction in ionic transport in the electrodes, limiting the diffusion kinetics of Li+ and the utilization rate of active substances. In this study, lithium‐ion‐exchanged zeolite X (Li‐X zeolite) is synthesized via Li+ exchange strategy to enhance Li+ diffusion kinetics. When incorporated Li–X zeolite into the ultra‐high loading cathodes, it possesses i) high electron conductivity with a uniform network by reducing tortuosity, ii) decent ion conductivity attributes to modulated Li+ diffusivity of Li‐X and iii) high elasticity to prevent particle‐level cracking and electrode‐level disintegration. Moreover, Li–X zeolite at the solid/liquid interface facilitates the formation of a stable cathode electrolyte interface, which effectively suppresses side reactions and mitigates the dissolution of transition cations. Therefore, an ultra‐high loading (66 mg cm−2) cathode is fabricated via dry electrode technology, demonstrating a remarkable areal capacity of 12.7 mAh cm−2 and a high energy density of 464 Wh kg−1 in a lithium metal battery. The well‐designed electrode structure with multifunctional Li–X zeolite as an additive in thick cathodes holds promise to enhance the battery's rate capability, cycling stability, and overall energy density.