Uniform Solid Electrolyte Interphase Research Articles

Fluorinated Surface Engineering towards High-rate and Durable Potassium-ion Battery.

Solid electrolyte interphase (SEI) crucially affects the rate performance and cycling lifespan, yet to date more extensive research is still needed in potassium-ion batteries. We report an ultra-thin and KF-enriched SEI triggered by tuned fluorinated surface design in electrode. Our results reveal that fluorination engineering alters the interfacial chemical environment to facilitate inherited electronic conductivity, enhance adsorption ability of potassium, induce localized surface polarization to guide electrolyte decomposition behavior for SEI formation, and especially, enrich the KF crystals in SEI by self-sacrifice from C-F bond cleavage. Hence, the regulated fluorinated electrode with generated ultra-thin, uniform, and KF-enriched SEI shows improved capacity of 439.3 mAh g-1 (3.82 mAh cm--2), boosted rate performance (202.3 mAh g-1 at 8.70 mA cm-2) and durable cycling performance (even under high loading of ~8.7 mg cm-2). We expect this practical engineering principle to open up new opportunities for upgrading the development of potassium-ion batteries.

Electrolyte solvent composition regulating endows CoSe2 hollow nanocage anode with stable potassium ion storage

Metal selenides are ideal anode materials for potassium-ion batteries (PIBs) due to their significant merits of favorable conductivity and ion transport property. However, the inevitable volume changes metal selenides electrode during potassiation/depotassiation processes result in the fracture and reconstruction of the solid electrolyte interphase (SEI) layer, causing capacity decay and significantly limiting their practical applications. Reasonable morphology control accompanied by uniform and rigid SEI layer formation are key factors in improving the electrochemical cycling stability of metal selenides. In this paper, nano-hollow CoSe2 (CoSe2@CNC) anode materials are prepared using ZIF-67 as the precursor. The differences of electrochemical performances for CoSe2@CNC anode material in ester-based and ether-based electrolytes have been investigated in detail. Results demonstrate that the SEI layer formed in the ester-based electrolyte is loose and thick, leading to electrode pulverization and material detachment after several cycles, resulting in rapid degradation of cycle performance. In contrast, a thin and inorganic-rich SEI layer containing more inorganic components is formed in the ether-based electrolyte, effectively protecting the electrode from damage, facilitating electronic transfer at the electrode electrolyte interphase, and optimizing potassium ions storage performance.

1,3,6-Hexanetricarbonitrile as electrolyte additive to inhibit sodium dendrites in sodium-metal batteries

Sodium-metal batteries (SMBs) offer substantial competitiveness owing to their wide elemental distribution and high specific capacity. However, SMBs face safety issues such as unstable properties of the Solid Electrolyte Interphase (SEI) layer due to irregular sodium dendrites. In this paper, we constructed a stable and uniform SEI layer by introducing the 1,3,6-Hexanetricarbonitrile (HTCN) electrolyte additive, replacing the conventional, insoluble nitrate. HTCN facilitates the generation of substances like Na3N with high electrical conductivity on the Na anode surface. This accelerates Na+ shuttling and provides high-flux nucleation sites. Molecular dynamics simulations were employed to elucidate the solvated structure of electrolyte and radial distribution of Na+ after HTCN addition. Moreover, in-situ optical microscopy revealed a stable and robust SEI layer, effectively inhibiting the disorderly growth of sodium dendrites. The superior cycling performance of the Na3V2(PO4)3 (NVP)/Na full cell further demonstrates the addition of HTCN.

Binary Solvent Induced Stable Interphase Layer for Ultra-Long Life Sodium Metal Batteries.

Sodium foil, promising for high-energy-density batteries, faces reversibility challenges due to its inherent reactivity and unstable solid electrolyte interphase (SEI) layer. In this study, a stable sodium metal battery (SMB) is achieved by tuning the electrolyte solvation structure through the addition of co-solvent 2-methyl tetrahydrofuran (MTHF) to diglyme (Dig). The introduction of cyclic ether-based MTHF results in increased anion incorporation in the solvation structure, even at lower salt concentrations. Specifically, the anion stabilization capabilities of the environmentally sustainable MTHF co-solvent lead to a contact-ion pair-based solvation structure. Time-of-flight mass spectroscopy analysis reveals that a shift toward an anion-dominated solvation structure promotes the formation of a thin and uniform SEI layer. Consequently, employing a NaPF6-based electrolyte with a Dig:MTHF ratio of 50% (v/v) binary solvent yields an average Coulombic efficiency of 99.72% for 300 cycles in Cu||Na cell cycling. Remarkably, at a C/2 cycling rate, Na||Na symmetric cell cycling demonstrates ultra-long-term stability exceeding 7000 h, and full cells with Na0.44MnO2 as a cathode retain 80% of their capacity after 500 cycles. This study systematically examines solvation structure, SEI layer composition, and electrochemical cycling, emphasizing the significance of MTHF-based binary solvent mixtures for high-performance SMBs.

Fluorine-Terminated Self-Assembled Monolayers Grafted Graphite Anode Inducing a LiF-Dominated SEI Inorganic Layer for Fast-Charging Lithium-Ion Batteries.

The electrochemical kinetic processes of Li+ ions, including the desolvation of the Li+ ions from the electrolyte to the solid electrolyte interphase (SEI), the transportation of desolvated Li+ ions across the SEI, and the charge transfer at the interface between the SEI and graphite, determine the rate performance and cycling stability of the graphitic anode in lithium-ion batteries (LIBs). In this work, fluorine-terminated self-assembled monolayers were grafted on the surface of spherical graphite particles to regulate the chemical composition and structure of SEI formed on the graphite surface in the presence of conventional ester electrolytes. The comprehensive characterization and first-principles calculation results illustrate that a uniform LiF-dominated SEI film can be generated on the as-functionalized graphite anode due to the carbon-fluorine bonds' cleavage of fluorine-terminated self-assembled monolayers. The LiF-dominated SEI film is particularly beneficial for desolvated lithium-ion transport across the SEI, affording LiCoO2//graphite full cells with substantially enhanced fast-charging capability and cycle stability. This strategy should be potentially useful for modifying other anode materials to regulate the interfacial chemistry between the anode and electrolyte in lithium-ion batteries.

In situ construction of robust artificial solid-electrolyte interphase layer on lithium-metal anode by a facile one-step solution route

Development of high energy density lithium-metal batteries (LMBs) is markedly hindered by the interfacial instability on lithium-metal anode side. Solid-electrolyte interphase (SEI) is a fundamental factor to regulate dendrite growth and enhance the stability of lithium-metal anodes. Here, trithiocyanuric acid, a triazine derivative with sulfhydryl groups, is used as an efficient promoter to favor the construction of a robust artificial SEI layer on the lithium metal surface, which greatly benefits the stability and efficiency of LMBs. With the assistance of trithiocyanuric acid facilely introduced on the Li surface via a one-step solution route, a highly uniform artificial SEI layer rich in Li2S and Li3N is formed, which efficiently facilitates uniform lithium deposition and suppresses lithium dendrite growth. Remarkably, the Li|Li cell displays stable lithium plating/stripping cycling over 800 h at 0.5 mA cm−2, 1 mAh cm−2, and the Li|LFP cells exhibit prolonged lifespan over 700 cycles at 3 C and superior rate performance from 2 to 20 C. This work provides a facile design strategy for constructing a superb artificial SEI layer for high-performance LMBs.

Insights into the multi-functional lithium difluoro(oxalate)borate additive in boosting the Li-ion reaction kinetics for Li3VO4 anodes.

The rational design of a solid electrolyte interphase (SEI) with high ionic conductivity and high electrochemical stability is significantly important in improving the electrochemical performance of anode materials. Herein, lithium difluoro(oxalate)borate (LiDFOB) is used as an electrolyte additive to generate protective SEI films on Li3VO4 (LVO) anodes. The addition of LiDFOB is beneficial to form a dense, uniform, stable and LiF-richer SEI, which is helpful to boost the Li-ion storage kinetics. In addition, the generated SEI can inhibit the further decomposition of electrolytes and maintain the morphology of LVO anodes during charge/discharge processes. As a result, LVO-based anodes exhibit a much higher capacity (769.5 mA h g-1 at 0.5 A g-1), enhanced rate performance (243.3 mA h g-1 at 5.0 A g-1) and excellent long-term cycling stability (209.9 mA h g-1 after 5000 cycles) when cycled in 1 wt% LiDFOB addition electrolyte. This work confirms that LiDFOB is a promising multi-functional additive for LiPF6 electrolytes and provides new insights into SEI construction towards high-performance LVO anodes.

Delineating the Impact of Transition-Metal Crossover on Solid-Electrolyte Interphase Formation with Ion Mass Spectrometry.

Lithium-metal batteries (LMB) employing cobalt-free layered-oxide cathodes are a sustainable path forward to achieving high energy densities, but these cathodes exhibit substantial transition-metal dissolution during high-voltage cycling. While transition-metal crossover is recognized to disrupt solid-electrolyte interphase (SEI) formation on graphite anodes, experimental evidence is necessary to demonstrate this for lithium-metal anodes. In this work, advanced high-resolution 3D chemical analysis is conducted with time-of-flight secondary-ion mass spectrometry (TOF-SIMS) to establish spatial correlations between the transition metals and electrolyte decomposition products found on cycled lithium-metal anodes. Insights into the localization of various chemistries linked to crucial processes that define LMB performance, such as lithium deposition, SEI growth, and transition-metal deposition are deduced from a precise elemental and spatial analysis of the SEI. Heterogenous transition-metal deposition is found to perpetuate both heterogeneous SEI growth and lithium deposition on lithium-metal anodes. These correlations are confirmed across various lithium-metal anodes that are cycled with different cobalt-free cathodes and electrolytes. An advanced electrolyte that is stable to higher voltages is shown to minimize transition-metal crossover and its effects on lithium-metal anodes. Overall, these results highlight the importance of maintaining uniform SEI coverage on lithium-metal anodes, which is disrupted by transition-metal crossover during operation at high voltages.

Synergistic Effect of Lithium (difluoromethanesulfonyl)(trifluoromethanesulfonyl)Imide (LiDFTFSI) and Vinylene Carbonate (VC) on High Performance of NMC811║Graphite Cells

Lithium-ion batteries (LIBs) have gained increasing importance in energy storage systems, driven by the growing demands of grid storage, automotive, and portable consumer applications. To meet the need for high energy density batteries, one promising approach involves the utilization of high capacity layered transition metal oxide cathodes, such as nickel-rich LiNi0.8Mn0.1Co0.1O2 (NMC811), which can deliver a high reversible specific capacity of over 180 mAh·g-1 [1,2]. However, due to the structural and interfacial instability[3], nickel-rich NMC cathode still faces challenges in long-term galvanostatic cycling. For these reasons, design of novel electrolyte formulations, which enable formation of an effective cathode electrolyte interphase (CEI), is highly desirable. Recent studies have highlighted the cross-talk between the cathode and anode, indicating that the evolution of the solid electrolyte interphase (SEI) can impact the formation of the CEI[4]. Thus, establishing an effective SEI/CEI pair is essential for achieving long-term cycling of nickel-rich NMC cathode-based cells. Electrolyte optimization plays a crucial role in facilitating the formation of a desirable SEI/CEI pair, leading to an improved cell performance and longevity. Lithium (difluoromethanesulfonyl)(trifluoro-methanesulfonyl)imide (LiDFTFSI) has proven to be promising in solid-polymer-electrolyte batteries due to the good SEI/CEI formation ability and suppressed Al-dissolution[5]. Additionally, LiDFTFSI exhibits also good compatibility with Li-metal batteries[6], heralding promising applications in Li-ion batteries. However, there is lack of systematic research investigating the potential impact of LiDFTFSI on the cathode as well as on resulting CEI formation and dynamics.In this work, we demonstrated enhanced galvanostatic cycling performance of NMC811||graphite cells achieved by utilizing LiDFTFSI and lithium hexafluorophosphate (LiPF6) in a blended salt organic carbonate-based electrolyte formulation. Comprehensive electrochemical and post mortem analysis revealed that the LiDFTFSI alone can effectively mitigate the structural changes in the NMC811 electrode by facilitating the formation of modified CEI. However, the continued growth of an inhomogeneous CEI, caused by the cross-talk effect between electrodes, adversely affected long-term cycling stability. To address this, vinylene carbonate (VC) was introduced to the electrolyte. Synergistic effect with LiDFTFSI leads to the formation of effective and uniform SEI and CEI. As a result, 720 charge/discharge cycles were achieved in NMC811||graphite cells with LiDFTFSI and VC containing electrolytes at 1C while maintaining 80% state-of-health (SOH80%).

MXene and silk fibroin peptide team up to build a 1+1>2 in situ SEI film

The utilization of solid-state lithium-ion batteries (SLIBs) is envisaged for the next generation of energy storage devices due to their exceptional energy density. Nonetheless, for practical applications of SLIBs, it is crucial to address the challenges associated with unstable interfaces and poor electrochemical performance. By employing silk fibroin peptide (SFP) and MXene, we successfully achieved the in-situ generation of uniform solid electrolyte interphase (SEI) films through the design of modified interfaces. The incorporation of -NH2 groups from SFP and the -F terminus from MXene facilitated the formation of Li3N and LiF, thereby enabling selective localization and controlled SEI film growth as confirmed by the time-of-flight secondary-ion mass spectrometry (TOF-SIMS) analysis. The Derjaguin-Müller-Toporov (DMT) modulus demonstrated the robustness of the SEI film. This phenomenon enhances interfacial stability, promotes lithium-ion nucleation, suppresses dendrite growth, and improves overall electrochemical performance during battery operation. The presence of -NH2 possessing a lone pair of electrons exhibited excellent lithophile properties that facilitated micro-complexes formation with lithium ions, thereby promoting lithium salt dissociation and facilitating the lithium-ion migration within systems. Furthermore, the interface-modified polymer electrolytes (PEs) demonstrated an impressive ionic conductivity of up to 1.16 × 10−3 S cm−1, along with a favorable transference number of lithium ions (tLi+) of 0.57. Notably, the modified PEs significantly contributed to stable battery operation at room temperature (RT), exhibiting an initial discharge capacity of 117.6 mAh g−1 at 5 C. This innovative strategy involving modification at the interface level represents a significant advancement towards achieving stable operation in high-energy SLIBs.

Demarcating the Impact of Electrolytes on High‐Nickel Cathodes and Lithium‐Metal Anode

AbstractThe ever‐growing demand for low‐cost, high‐energy‐density lithium‐ion batteries (LIBs) makes high‐nickel layered oxide cathodes, especially LiNiO2 (LNO), one of the most appealing candidates. However, poor structural and surface instability that leads to a short cycle life remains a formidable challenge. Herein, a systematic investigation of LNO performance in two different electrolytes (a conventional carbonate‐based LP57 electrolyte and an ether‐based localized high‐concentration electrolyte (LHCE)) with different charge cut‐off voltages is presented. These findings show that the cathode‐electrolyte reactivity is the main factor dictating the performance degradation of LNO at high voltages rather than bulk integrity. While LHCE can provide good stability beyond 4.2 V with a robust, uniform solid–electrolyte interphase (SEI) layer on the Li‐metal anode, there is no significant difference in cyclability at 4.15 V (96% capacity retention after 200 cycles) for both LP57 and LHCE. From LNO symmetric cells, carbonate‐based electrolyte is found to be good for LNO stability while ether‐based electrolyte is beneficial toward Li‐metal anode. Thus, a suitable electrolyte or a low cut‐off voltage is necessary to maintain a decent cycle life. Altogether, this work highlights the impact of electrolyte and cut‐off voltage on LNO and Li‐metal, which can help guide the development of cells based on LNO.

Hosting Li0 in an activated lithiophilic polymer matrix with electrodeposition regulating spaces for stable lithium metal anodes

The cyclability of rechargeable high-energy-density lithium (Li) metal batteries (LMBs) is seriously limited by the Li dendrite induced volume variation and safety hazards. Herein, a hierarchical host composed of a robust polyethylene terephthalate (PET) matrix as the primary backbone and carbon nanotube (CNT) sponges as the pore fillers is fabricated as an advanced model structure for highly reversible Li storage. Compared with the conventional three-dimensional hosts in which the Li deposition confinement is not controlled in the void pores, extremely smooth Li deposition can be accommodated in the CNT sponges of the confined spaces, leading to a step towards better Li protection. Furthermore, a niobium (Nb)-based coating is revealed as a rational process to not only enable uniform solid electrolyte interphase with fast Li+ migration ability of the PET-CNT-Nb host, but also to activate the abundant polar lithiophilic segments (CO or -O-) of the PET matrix for guided Li nucleation. Based on the multifunctional PET-CNT-Nb host, stable cycling of LMBs with a practical capacity of ∼2.5 mAh cm−2 can be achieved over 400 cycles, demonstrating the rationality of the investigated host structuration rule for great Li protection ability.

Multi-functions of amino thiophenol additives for shielding lithium metal anode in advanced Li-S battery

Lithium-sulfur (Li-S) batteries have been considered as a promising candidate for the next generation of battery systems due to their high specific capacity and energy density. However, some barriers impede the application of Li-S batteries, such as the “shuttle effects” of lithium polysulfides (LPS), the poor electrical conductivity of sulfur, and lithium dendrite formation on lithium metal electrodes. Herein, we investigated a series of amino thiophenol as electrolyte additives: 2-amino thiophenol (2-ATP), 3-amino thiophenol (3-ATP), and 4-amino thiophenol (4-ATP); as well as p-phenylenediamine (PPD). These additives react with Li to form a stable and uniform solid electrolyte interphase (SEI) to protect the Li anode and minimize the interaction of Li with soluble LPS. Initial specific capacity at 0.1C and reversible specific capacity after 100 cycles are 1420 and 1043 mAh/g, 1429 and 982 mAh/g, 1148 and 871 mAh/g, 1317 and 791 mAh/g for 4-ATP, 3-ATP, 2-ATP, and PPD, respectively. Long-term cycling testing of Li-S cells was conducted at 0.2C and the cell with 4-ATP additives deliver an initial specific capacity of 1159 mAh/g and capacity retention of 77% after 300 cycles. The morphology and composition of the after-cycled SEI layers were examined by SEM and XPS. The findings suggest amino thiophenols (ATPs) form stable and smooth closed-packed SEI layers, that ameliorate lithium dendrite problems and LPS reactions with Li metal. 4-ATP is found to exhibit the best electrochemical performance followed by 3-ATP, 2-ATP, and PPD, which are in good agreement with the surface morphology. In addition, the amine group can assist the reaction between the thiol group and S8 on the cathode and modify the redox pathway of polysulfide.

Nonflammable electrolyte with low exothermic design for safer lithium-based batteries

Battery safety has always been a concern for high-energy-density configurations with nickel-rich cathode (Ni>0.6). Tremendous heat released from the reaction between highly flammable electrolyte and cathode under mechanical, thermal or electrical abuse may cause thermal runaway. Herein, we explore the heat release of various solvents with fully charged cathodes and summarized the solvent/heat release phase diagram. On this basis, we select fluorinated bis(2,2,2-trifluoroethyl) carbonate to prepare a nonflammable, low exothermic electrolyte. This electrolyte significantly reduces the maximum temperature by one-third and decreases the maximum heating rate from 206.0 °C s−1 to 82.6 °C s−1 during the thermal runaway process of commercial lithium-ion pouch cell. Moreover, it demonstrates remarkable compatibility with lithium metal anode. Benefited from the uniform solid-electrolyte interphase (SEI) rich in -CF3 organic layer, the Li||LiNi0.8Co0.1Mn0.1O2 (NCM811) full cell exhibits a capacity retention rate of 80% after 240 cycles. Notably, a 1.5 Ah Li metal pouch cell with a high energy density of 365 Wh kg−1 displays an excellent capacity retention of 90.02% after 98 cycles under realistic conditions. This work provides a novel approach to construct safer and longer-lasting lithium-based batteries by designing nonflammable and low exothermic electrolyte.

Firmly interlocked Janus-type metallic Ni3Sn2S2-carbon nanotube heterostructure suppresses polysulfide dissolution and Sn aggregation

Ternary transition-metal tin chalcogenides, with their diverse compositions, abundant constituents, high theoretical capacities, acceptable working potentials, excellent conductivities, and synergistic active/inactive multi-components, hold promise as anode materials for metal-ion batteries. However, abnormal aggregation of Sn nanocrystals and the shuttling of intermediate polysulfides during electrochemical tests detrimentally affect the reversibility of redox reactions and lead to rapid capacity fading within a limited number of cycles. In this study, we present the development of a robust Janus-type metallic Ni3Sn2S2-carbon nanotube (NSSC) heterostructured anode for Li-ion batteries (LIBs). The synergistic effects of Ni3Sn2S2 nanoparticles and a carbon network successfully generate abundant heterointerfaces with steady chemical bridges, thereby enhancing ion and electron transport, preventing the aggregation of Ni and Sn nanoparticles, mitigating the oxidation and shuttling of polysulfides, facilitating the reforming of Ni3Sn2S2 nanocrystals during delithiation, creating a uniform solid-electrolyte interphase (SEI) layer, protecting the mechanical integrity of electrode materials, and ultimately enabling highly reversible lithium storage. Consequently, the NSSC hybrid exhibits an excellent initial Coulombic efficiency (ICE > 83 %) and superb cyclic performance (1218 mAh/g after 500 cycles at 0.2 A/g and 752 mAh/g after 1050 cycles at 1 A/g). This research provides practical solutions for the intrinsic challenges associated with multi-component alloying and conversion-type electrode materials in next-generation metal-ion batteries.

Effect of Salt Concentration on the Interfacial Solvation Structure and Early Stage of Solid–Electrolyte Interphase Formation in Ca(BH4)2/THF for Ca Batteries

The Ca2+ solvation structure at the electrolyte/electrode interface is of central importance to understand electroreduction stability and solid-electrolyte interphase (SEI) formation for the novel multivalent Ca battery systems. Using an exemplar electrolyte, the concentration-dependent solvation structure of Ca(BH4)2-tetrahydrofuran on a gold model electrode has been investigated with various electrolyte concentrations via electrochemical quartz crystal microbalance with dissipation (EQCM-D) and X-ray photoelectron spectroscopy (XPS). For the first time, in situ EQCM-D results prove that the prevalent species adsorbed at the interface is CaBH4+ across all concentrations. As the salt concentration increases, the number of BH4- anions associated with Ca2+ increases, and much larger solvated complexes such as CaBH4+·4THF or Ca(BH4)3-·4THF form at the interface at high concentrations prior to Ca plating. Different interfacial chemistries lead to the formation of SEIs with different components demonstrated by XPS. High electrolyte concentrations reduce the solvent decomposition and promote the formation of thick, uniform, and inorganic-rich (i.e., CaO) SEI layers, which contribute to improved Ca plating efficiency and current density in electrochemical measurements.

Inhibiting gas generation to achieve ultralong-lifespan lithium-ion batteries at low temperatures

•Revealing the gas generation mechanism in low-temperature lithium-ion batteries •Proposing a high-concentration electrolyte strategy to inhibit gas generation •The Ah-level pouch cell exhibits a record-breaking lifespan of over 1 year at −20°C The notorious low-temperature sensitivity of contemporary lithium-ion batteries (LIBs) has long restricted their low-temperature applications. Introduction of high-content low-freezing-point solvents significantly expands the low-temperature operation border of LIBs. However, they react violently with metallic lithium (Li) plated at low temperatures (−20°C or lower), resulting in severe gas generation and a limited lifespan. We reveal the mechanism of gas generation and develop a high-concentration ethyl acetate (EA)-based electrolyte. The dense and uniform solid electrolyte interphase formed by the joint decomposition of rich anions and additive effectively passivate the plated Li at low temperatures. The proposed electrolyte enables the LiNi0.8Co0.1Mn0.1O2 (NCM811)/graphite pouch cell to be stably cycled at −20°C and 0.2 C for a record-breaking lifetime of more than 1 year (1,400 cycles). The NCM811/graphite pouch cell exhibits good fast-charging capability (0.5 C) at −20°C with a capacity decay rate as low as 0.0097% per cycle during 4,000 cycles. The notorious low-temperature sensitivity of contemporary lithium-ion batteries (LIBs) has long restricted their low-temperature applications. Introduction of high-content low-freezing-point solvents significantly expands the low-temperature operation border of LIBs. However, they react violently with metallic lithium (Li) plated at low temperatures (−20°C or lower), resulting in severe gas generation and a limited lifespan. We reveal the mechanism of gas generation and develop a high-concentration ethyl acetate (EA)-based electrolyte. The dense and uniform solid electrolyte interphase formed by the joint decomposition of rich anions and additive effectively passivate the plated Li at low temperatures. The proposed electrolyte enables the LiNi0.8Co0.1Mn0.1O2 (NCM811)/graphite pouch cell to be stably cycled at −20°C and 0.2 C for a record-breaking lifetime of more than 1 year (1,400 cycles). The NCM811/graphite pouch cell exhibits good fast-charging capability (0.5 C) at −20°C with a capacity decay rate as low as 0.0097% per cycle during 4,000 cycles.

Self-Assembly Monolayer Inspired Stable Artificial Solid Electrolyte Interphase Design for Next-Generation Lithium Metal Batteries.

Lithium metal is widely regarded as the "ultimate" anode for energy-dense Li batteries, but its high reactivity and delicate interface make it prone to dendrite formation, limiting its practical use. Inspired by self-assembled monolayers on metal surfaces, we propose a facile yet effective strategy to stabilize Li metal anodes by creating an artificial solid electrolyte interphase (SEI). Our method involves dip-coating Li metal in MPDMS to create an SEI layer that is rich in inorganic components, allowing uniform Li plating/stripping under a low overpotential over 500 cycles in carbonate electrolytes. In comparison, pristine Li metal shows a rapid increase in overpotential after merely 300 cycles, leading to failure soon after. Molecular dynamics simulations demonstrate that this uniform artificial SEI suppresses Li dendrite formation. We further demonstrated its enhanced stability pairing with LiFePO4 and LiNi1-x-yCoxMnyO2 cathodes, highlighting the proposed strategy as a promising solution for practical Li metal batteries.

Influence of Potassium Metal-Support Interactions on Dendrite Growth.

Combined synchrotron X-ray nanotomography imaging, cryogenic electron microscopy (cryo-EM) and modeling elucidate how potassium (K) metal-support energetics influence electrodeposit microstructure. Three model supports are employed: O-functionalized carbon cloth (potassiophilic, fully-wetted), non-functionalized cloth and Cu foil (potassiophobic, nonwetted). Nanotomography and focused ion beam (cryo-FIB) cross-sections yield complementary three-dimensional (3D) maps of cycled electrodeposits. Electrodeposit on potassiophobic support is a triphasic sponge, with fibrous dendrites covered by solid electrolyte interphase (SEI) and interspersed with nanopores (sub-10 nm to 100 nm scale). Lage cracks and voids are also a key feature. On potassiophilic support, the deposit is dense and pore-free, with uniform surface and SEI morphology. Mesoscale modeling captures the critical role of substrate-metal interaction on K metal film nucleation and growth, as well as the associated stress state.

Influence of Potassium Metal‐Support Interactions on Dendrite Growth

AbstractCombined synchrotron X‐ray nanotomography imaging, cryogenic electron microscopy (cryo‐EM) and modeling elucidate how potassium (K) metal‐support energetics influence electrodeposit microstructure. Three model supports are employed: O‐functionalized carbon cloth (potassiophilic, fully‐wetted), non‐functionalized cloth and Cu foil (potassiophobic, nonwetted). Nanotomography and focused ion beam (cryo‐FIB) cross‐sections yield complementary three‐dimensional (3D) maps of cycled electrodeposits. Electrodeposit on potassiophobic support is a triphasic sponge, with fibrous dendrites covered by solid electrolyte interphase (SEI) and interspersed with nanopores (sub‐10 nm to 100 nm scale). Lage cracks and voids are also a key feature. On potassiophilic support, the deposit is dense and pore‐free, with uniform surface and SEI morphology. Mesoscale modeling captures the critical role of substrate‐metal interaction on K metal film nucleation and growth, as well as the associated stress state.