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Electrolytes with high stability against both Li anode and high‐voltage cathode are critical for high‐energy and long‐cycling lithium metal batteries (LMBs). However, the free active solvents in common electrolytes are susceptible to decomposition at both Li anode and high‐voltage cathode. Although recently developed locally high‐concentration electrolytes (LHCEs) have largely restricted active solvents via Li+ coordination, the free molecules are still released upon the desolvation of Li+ at the surface of electrodes, causing continuous decomposition during long‐cycling processes. Here, a molecule competitive solvation electrolyte (MCE) is shown to stabilize high‐voltage LMBs by introducing a well‐designed and newly synthetic bipolar solvent molecule with one ion‐dissociative polar head and the other highly fluorinated nonpolar tail. The bipolar molecules competitively dissociate Li+ via weak coordination interactions, drastically reducing the ratio of active solvents in electrolytes and the detrimental decomposition at electrodes during the desolvation processes. Consequently, the MCE enables a 1.4‐Ah Li metal pouch cell with a stack energy density of 450 Wh kg−1 along with exceptional operation stability over 400 cycles (retention: 81%). Furthermore, the MCE also maintains the stable operation of a 2.5‐Ah Li‐S pouch cell with an excellent energy density of 417 Wh kg−1 for 70 cycles under practical conditions. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries (LSBs) have received great attention as promising candidates for next-generation energy-storage systems due to their high theoretical energy density. However, their practical energy density is limited by a large electrolyte-to-sulfur (E/S) ratio (>10 µL electrolyte/mg s), and their cycle performance encounters challenges from electrode passivation and Li dendrite formation. In this work, a dual-functional electrolyte additive of tetraethylammonium nitrate (TEAN) is presented to address these issues. NO3− as a high-donor-number (DN) salt anion can promote polysulfide dissolution, increase sulfur utilization, and alleviate electrode passivation. The tetraethylammonium cation can adsorb around Li protrusions to form a lithiophobic protective layer to inhibit the formation of Li dendrites. TEAN LSBs show improving capacity, cycling stability, and higher coulombic efficiency under lean electrolyte (5 μL electrolyte/mg s) conditions. [ABSTRACT FROM AUTHOR]

All‐solid‐state lithium batteries (ASSBs) enabled by solid‐state electrolytes (SEs) including oxide‐based and sulfide‐based electrolytes have gained worldwide attention because of their intrinsic safety and higher energy density over conventional lithium‐ion batteries (LIBs). However, despite the high ionic conductivity of advanced SEs, ASSBs still exhibit high overall internal resistance, the most significant contributor of which can be ascribed to the cathode‐SE interfaces. This review seeks to clarify the critical issues regarding the cathode‐SE interfaces, including fundamental principles and corresponding solutions. First, major issues concerning electro‐chemo‐mechanical instability between cathodes and SEs and their formation mechanisms are discussed. Then, specific problems in oxides and sulfides and various solutions and strategies toward interfacial modifications are highlighted. Efforts toward the characterization and analysis of cathode‐SE interfaces with advanced techniques are also summarized. Finally, perspectives are offered on several problems demanding urgent solutions and the future development of SE applications and ASSBs. [ABSTRACT FROM AUTHOR]

The realization of high‐performance thick S cathodes is a critical step to achieve high energy density lithium–sulfur (Li–S) batteries. However, it normally requires a complicated and time‐consuming fabrication processes to obtain high‐performance S cathodes with high mass loading. On the other hand, thick S cathodes fabricated with high‐speed slurry coating method show poor flexibility, capacity, and cycle life due to unpredictable electrode cracking. Herein, an industrial‐speed cracking‐controlled slurry coating method to generate mosaic‐like cracks in the S cathode is developed, which provides vertical channels to facilitate the rapid diffusion of electrolyte, adequate space to accommodate the volume expansion during cycling, and strain‐releasing structure to achieve high flexibility. With this simple method, thick Mosaic‐S cathodes (9 mAh cm−2) provide outstanding energy density, long cycle life, and outstanding flexibility under dynamic bending. This work paves the way for scalable fabrication of high‐performance S cathodes in the near future. [ABSTRACT FROM AUTHOR]

Lithium‐ion batteries (LIBs) have been occupying the dominant position in energy storage devices. Over the past 30 years, silicon (Si)‐based materials are the most promising alternatives for graphite as LIB anodes due to their high theoretical capacities and low operating voltages. Nevertheless, their extensive volume changes in battery operation causes the structural collapse of Si‐based electrodes, as well as severe side reactions. In this review, the preparation methods and structure optimizations of Si‐based materials are highlighted, as well as their applications in half and full cells. Meanwhile, the developments of promising electrolytes, binders and separators that match Si‐based electrodes in half and full cells have made great progress. Pre‐lithiation technology has been introduced to compensate for irreversible Li+ consumption during battery operation, thereby improving the energy densities and lifetime of Si‐based full cells. More importantly, almost all related mechanisms of Si‐based electrodes in half and full cells are summarized in detail. It is expected to provide a comprehensive insight on how to develop high‐performance Si‐based full cells. The work can help us understand what happens during the lithiation process, the primary causes of Si‐based half and full cells failure, and strategies to overcome these challenges. [ABSTRACT FROM AUTHOR]

Abstract Silicon is one of the most promising anode materials for the next-generation high energy density lithium-ion batteries as its superior specific capacity and ultralow lithiation/delithiation voltage. Whereas, silicon suffers massive volume change during cycling, resulting in drastic pulverization of active material and iterative growth of solid electrolyte interphase, largely limiting their widely applications. To address the challenge, water-soluble glycinamide modified PAA (PAA-GA) is synthesized through a facile and low-cost coupling method as a polymer binder to assemble silicon anode for alleviating its huge volume change. The carboxyl and double amide groups of the PAA-GA can form hydrogen bonds with the hydration layer of silicon, and meanwhile the double amide groups of PAA-GA can form double hydrogen bonds via interchain cohesion. These strong supramolecular interactions are reversible and can recover the dissociated bonds more efficiently upon the elimination of the mechanical stress. The PAA-GA-based silicon electrodes exhibit excellent cycling stability and high coulombic efficiency, demonstrating the PAA-GA binder being great potential in fabricating high energy density silicon anodes for next-generation lithium-ion batteries. Graphical abstract Image 1 Highlights • Glycinamide-based binder was synthesized via a facile coupling method. • Water-soluble binders were used for silicon anodes in lithium ion batteries. • A high capacity and good cyclestability were achieved by using the modified binder. [ABSTRACT FROM AUTHOR]

Garnet-based all-solid-state lithium batteries are expected to achieve high energy density and safety. However, the distinctly different chemical and electrochemical environment between the electrodes and garnet-type Li 6·4 La 3 Zr 1·6 Ta 0·4 O 12 (LLZTO) electrolyte results in high interfacial impedance that greatly hinders the electrochemical performance. Herein, we propose an asymmetrical interface modification strategy by respectively introducing an ultrathin in-situ polymerized interlayer on the cathode side and a lithiophilic liquid metal coating layer on the Li metal anode side. As a result, the interfacial impedance on both side is significantly reduced to 214 Ω cm2 on the cathode side and 7.45 Ω cm2 on the Li metal anode side due to the intimate contact and enhanced wettability between Li metal and GSSE together with improved conformability on the cathode side and Li ion conductance within the cathode. Therefore, the interface modified LiFePO 4 ||LLZTO||Li all-solid-state battery exhibits excellent cycling performance over 150 cycles with capacity retention of 96.7% and small voltage polarization of 55 mV at 0.1C and 60 °C. This work provides a convenient strategy to alleviate the interfacial issues in all-solid-state batteries. • Asymmetrical modification layers are introduced between electrolyte and electrodes. • Low impedance of 213.9 Ω cm2 is achieved with in-situ polymerized interlayer. • Impedance of 7.45 Ω cm2 on anode side is realized with liquid metal coating layer. • LFP.||SPE@LLZTO@LM||Li battery has capacity retention of 96.7% after 150 cycles. • The battery also shows a small voltage polarization of 55 mV at 0.1C and 60 °C. [ABSTRACT FROM AUTHOR]

• Flexible solid-state cells are developed with an in situ integration strategy. • A 20-µm-thick hybrid polymer/ceramic/ionic liquid electrolyte is prepared. • Stable interfaces are built, keeping intimate contact and reducing resistance. • The Li 4 Ti 5 O 12 /LiNi 0.8 Co 0.1 Mn 0.1 O 2 cell exhibits long cycling life at 30 °C. • The use of Si-based anode achieves 489.6 Wh kg−1 energy density at material's level. Flexible solid-state batteries (FSSBs) are indispensable energy storage devices to fulfil the energy and safety requirements for future flexible applications. The bottlenecks of FSSBs are how to realize high energy density with competent ionic conductivity for room-temperature (RT) flexible applications. Here, the first fabrication of RT FSSB with high energy density is reported, which is realized by in situ integration of a 20-µm-thick hybrid polymer/ceramic/ionic liquid solid-state electrolyte (SSE) between the high energy combination of anode/cathode electrodes. The in situ electrode/electrolyte interfacial integration strategy provides an ultrathin SSE layer, ultralow resistance and superior flexibility, and the SSE guarantees both high ionic conductivity and good compatibility with high-energy cathode LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811). The fabricated Li 4 Ti 5 O 12 /NCM811 FSSB delivers super-low resistance approaching conventional liquid cells and excellent cycling stability up to 600 cycles at RT. The extension of anode to SiO x @graphite leads to a high theoretical energy density of 489.6 Wh kg−1 at material's level, times higher than current options. In addition, the RT FSSB shows great flexibility, indicating a high performance application in future flexible electronics. [ABSTRACT FROM AUTHOR]

[Display omitted] • Robust chemical combination and space confinement effect in MGS-M nanocomposites. • Highly oxidized Mn 3 O 4 and increased Li+ active sites improve the specific capacity. • High pseudocapacitance contribution favors the rate capacity and cycle life. • Amorphous phase provides more Li+ active sites, diffusion paths and voids. Mn 3 O 4 -based materials have been broadly investigated as anode materials for lithium- ion batteries (LIBs) due to their high energy densities, affordable cost, environmental benignity, etc. However, the wide voltage hysteresis due to inferior electronic conductivity and serious volume expansion during lithiation/delithiation seriously restricted their practical applications. In this work, Mn 3 O 4 /graphene sheet (MGS) nanocomposites were prepared by a solution reaction assisted calcination method, which led to superior electrochemical performance for LIBs and presented both high reversible capacity and excellent cyclic stability (1199.5 mAh g−1 after 600 cycles and 995.3 mAh g−1 after 1000 cycles at a current density of 500 mA g−1). The superior cyclic stability could be attributed to the amorphization effect of Mn 3 O 4 and strong coupling interaction between Mn 3 O 4 and graphene sheets. On one hand, the highly oxidized Mn 3 O 4 and increasing Li+ active sites during extended cycles are beneficial to achieve high specific capacity. Meanwhile, the strong coupling effect, fast pseudocapacitive reaction and amorphous phase effect help provide numerous voids, which effectively alleviate volume expansion and enable excellent cyclic stability, enriching their great opportunities for LIBs anode materials with narrow voltage hysteresis and long cycle life. [ABSTRACT FROM AUTHOR]

High-performance electrode materials with intelligent design hold the promise for the development of lithium ion batteries regarding high energy density and long cycling life. Herein, we report an artificial solid electrolyte interphase (SEI) modified porous SiO x anode (P-SiO x) prepared by a facile in-situ polymerization of tannin (PTN) under alkaline condition, forming an elastic polymer layer surrounding P-SiO x particles. The as-prepared P-SiO x @PTN composite demonstrates higher initial Coulombic efficiency (ICE) and stronger mechanical property than the P-SiO x. Consequently, the outer elastic and electric buffer layer ensures the composite showing a high reversible capacity of 1616 mAh g−1 at 0.1 C and exceptional long-term cycling performance. Moreover, when coupled with LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathode, high reversible capacity (123 mAh g−1) and good capacity retention (83 mAh g−1 after 300 cycles) at 0.5 C are achieved. This facile method constructing the artificial solid electrolyte interphase with enhanced mechanical and electrochemical properties by the in-situ PTN is of great promise for Si-based anode materials. Unlabelled Image • An artificial solid electrolyte interphase modified SiO x composite is prepared. • The artificial layer ensures the structure stability of the SiO x composite. • The as-prepared SiO x composite exhibits excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

LiNi 0.6 Mn 0.2 Co 0.2 O 2 attracts increasing attention in industry due to its high energy density. Vinylene carbonate and 1,3-propane sultone are engaged to enhance the high-temperature performance of LiNi 0.6 Mn 0.2 Co 0.2 O 2 /artificial graphite pouch cells in this work. With the addition of the additives, the capacity retention of the full cell reaches 98% after 200 cycles at 45 °C and 500 mA. Meanwhile, the underneath mechanism is investigated by employing X-ray photoelectron spectroscopy, gas chromatograph-mass spectrometer and liquid chromatography-quadruple time of flight mass spectrometry measurements. The results show that the additives can not only protect the anode, but also shelter the cathode. It is of great interest that vinylene carbonate can suppress the decomposition of electrolyte, leading to less organic species in electrolyte, more stable interfaces. The addition of 1,3-propane sultone takes part in the generation of sulfonates after formation, which can be reduced to sulfides upon cycling. The combination of these two additives can optimize the interfacial reactions, as well as can suppress the decomposition of electrolytes and the dissolution of manganese, which leads to much better high-temperature storage performance and cycling performance of the full cells. Image 1 • VC and PS as electrolyte additives in NMC622/graphite cells are investigated. • Capacity retention is 98% after 200 cycles at 0.5 C and 45 °C with VC and PS. • The thicker CEI can prevent Mn dissolution more effectively. • Sulfonates on anode are reduced to sulfides upon cycling. [ABSTRACT FROM AUTHOR]