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Lithium–metal batteries (LMBs) have garnered significant interests for their promising high gravimetric energy density (Eg) ∼ 750 Wh kg−1. However, the practical application of the LMBs is plagued by the high reactivity and large volume change during charging–discharging of the lithium–metal anode (LMA), seriously deteriorating the battery safety and cycle life. Great efforts have been devoted to tailoring the electrolytes to favor the Li–metal electroplating by uniformizing the deposition morphology and by suppressing the side reactions between electrolytes and LMA. The aggressive chemistries of both the LMA and its high‐voltage counterpart give new electrolyte components more opportunities, especially designing via molecular engineering. Here, a comprehensive and in‐depth overview of the scientific challenges, fundamental mechanisms, and particularly historical strategies of designing new molecules for electrolyte components including solvents, salts, and additives. Their important roles in tuning the Li+ solvation structure, interface composition, decomposition pathways, and the resultant electrochemical performance of LMBs are also presented. Finally, novel insights and promising research directions from the practical application viewpoints are proposed for future electrolyte designs for high‐voltage LMBs. [ABSTRACT FROM AUTHOR]

Combining Li‐metal anodes (LMAs) with high‐voltage Ni‐rich layered‐oxide cathodes is a promising approach to realizing high‐energy‐density Li secondary batteries. However, these systems experience severe capacity decay due to structural degradation of high‐voltage cathodes and side reactions of electrolyte solutions with both electrodes. Herein, the use of multi‐functional additives in fluoroethylene carbonate‐based electrolyte solutions that enable the operation of successfully rechargeable high‐voltage (4.5 V) Li‐metal batteries (LMBs) with high areal capacity (>4 mAh cm−2) are reported. Customized electrolyte solutions are pivotal in passivating the electrodes, minimizing microcrack formation, and ensuring that current is uniformly distributed within cathode particles. The developed electrolyte solution protects the LMA by forming a very stable and effective solid–electrolyte interphase. Together with the Li[Ni0.78Co0.1Mn0.12]O2 cathode material, which is composed of radially aligned rod‐shaped primary particles, the developed high‐voltage LMB containing 20 mg cm−2 of cathode material delivers a high specific capacity of 230 mAh g−1 at 0.1 C and retains >86% of its initial capacity after 200 cycles at 0.5 C. This study highlights the significance of controlling the interfacial structure via electrolyte solution modification and the use of cathode materials with engineered morphologies that enhance mechanical stability. [ABSTRACT FROM AUTHOR]

The strategic formulation of a compatible electrolyte plays a pivotal role in extending the longevity of lithium‐metal batteries (LMBs). Here, we present findings on a partially fluorinated electrolyte distinguished by a subdued solvation affinity towards Li+ ions and a concentrated anion presence within the primary solvation layer. This distinctive solvation arrangement redirects the focal points of reactions from solvent molecules to anions, facilitating the predominant involvement of anions in the creation of a LiF‐enriched solid‐electrolyte interphase (SEI). Electrochemical assessments showcase effective Li+ transport kinetics, diminished overpotential polarization for Li nucleation (28 mV), and prolonged cycling durability in Li||Li cells employing the partially fluorinated electrolyte. When tested in Li||NCM811 cells, the designed electrolyte delivers a capacity retention of 89.30 % and exhibits a high average Coulombic efficiency of 99.80 % over 100 cycles with a charge‐potential cut‐off of 4.6 V vs. Li/Li+ under the current density of 0.4C. Furthermore, even at a current density of 1C, the cells maintain 81.90 % capacity retention and a high average Coulombic efficiency of 99.40 % after 180 cycles. This work underscores the significance of weak‐solvation interaction in partially fluorinated electrolytes and highlights the crucial role of solvent structure in enabling the long‐term stability and high‐energy density of LMBs. [ABSTRACT FROM AUTHOR]

Polymer electrolytes (PEs) are widely used in the field of flexible energy storage due to their high safety, good flexibility, and ease of processing. Developing PEs with both high mechanical properties, high ionic conductivity and wide electrochemical stability window (ESW) for lithium‐metal batteries (LMBs) is an urgent issue to be addressed. In this work, we designed and synthesized the poly (vinyl alcohol) (PVA)‐polyacrylic acid (PAA)‐LiCl electrolyte for LMBs with a high ionic conductivity, wide ESW, high modulus and puncture resistance simultaneously. Through the construction of dual cross‐linking networks, the PVA‐PAA‐LiCl exhibits a wide ESW (6.2 V), achieves a notable ionic conductivity (1.08 × 10−4 S cm−1) at room temperature and can realize a high cycle stability of Li symmetric battery more than 300 h at 1 mA cm−2/1 mA h cm−2. Furthermore, it demonstrates exceptional puncture resistance, capable of withstanding pressures up to 5.73 × 108 Pa exerted by a steel nail, while simultaneously exhibites a commendable tensile strength of 4.9 MPa. Hence, this conceptual framework featuring dual‐crosslink network structure offers profound implications for the progression of next‐generation flexible energy storage. [ABSTRACT FROM AUTHOR]

Lithium metal is regarded as ideal anode material due to its high theoretical specific capacity and low electrode potential. However, the uncontrollable growth of lithium dendrites seriously hinders the practical application of lithium-metal batteries (LMBs). Among various strategies, carbon nanofiber materials have shown great potential in stabilizing the lithium-metal anode (LMA) due to their unique functional and structural characteristics. Here, the latest research progress on carbon nanofibers (CNFs) for LMA is systematically reviewed. Firstly, several common preparation techniques for CNFs are summarized. Then, the development prospects, strategies and the latest research progress on CNFs for dendrite-free LMA are emphatically introduced from the perspectives of neat CNFs and CNF-based composites. Finally, the current challenges and prospects of CNFs for stabilizing LMA are summarized and discussed. These discussions and proposed strategies provide new ideas for the development of high-performance LMBs. [ABSTRACT FROM AUTHOR]

The practical application of solid‐state polymer lithium‐metal batteries (LMBs) is plagued by the inferior ionic conductivity of the applied polymer electrolytes (PEs), which is caused by the coupling of ion transport with the motion of polymer segments. Here, solvated molecules based on ionic liquid and lithium salt with strong Li+‐solvent interaction are inserted into an elaborately engineered perfluoropolymer electrolyte via ionic dipole interaction, extensively facilitating Li+ transport and improving mechanical properties. The intensified formation of solvation structures of contact ion pairs and ionic aggregates, as well as the strong electron‐withdrawal properties of the F atoms in perfluoropolymers, give the PE high electrochemical stability and excellent interfacial stability. As a result, Li||Li symmetric cells demonstrate a lifetime of 2500 h and an exceptionally high critical current density above 2.3 mA cm−2, Li||LiFePO4 batteries exhibit consistent cycling for 550 cycles at 10 C, and Li||uncoated LiNi0.8Co0.1Mn0.1O2 cells achieve 1000 cycles at 0.5 C with an average Coulombic efficiency of 98.45 %, one of the best results reported to date based on PEs. Our discovery sheds fresh light on the targeted synergistic regulation of the electro‐chemo‐mechanical properties of PEs to extend the cycle life of LMBs. [ABSTRACT FROM AUTHOR]

Liquid metals (LMs) with their unique properties are considered for a range of applications such as energy storage, catalysis, electronics, and biomedical engineering. Recently, the introduction of LMs into rechargeable batteries has not only proven to improve overall performance but also overcome commonly known challenges like low energy density, material degradation, interface failure, and poor system integrity. Specifically, room‐temperature LMs such as gallium (Ga), Ga‐based alloys (GBAs), and metallic mercury (Hg) are promising candidates in rechargeable batteries due to their low viscosity, high electrical and thermal conductivity, excellent deformability, superior electrochemical properties, and self‐healing capability. Herein, a review of recent advances in LMs for rechargeable batteries, starting with a brief introduction to LMs fundamentals and their properties is presented. Then, an extensive literature review is carried out to summarize the LMs' advances in addressing existing challenges of lithium‐ion, lithium‐metal, lithium–sulfur, and other rechargeable batteries. The current state of the art and future perspective are also put forward. It is believed that highlighting potential developments pertaining to LMs can fascinate researchers in exploring them for future rechargeable batteries. [ABSTRACT FROM AUTHOR]

The development of lithium–metal batteries (LMBs) has emerged as a mainstream approach for achieving high‐energy‐density energy storage devices. The stability of electrochemical interfaces plays an essential role in realizing stable and long‐life LMBs. Despite extensive and comprehensive research on the lithium anode interface, there is limited focus on the cathode interface, particularly regarding high‐voltage transition metal oxide cathode materials. In this review, the challenges associated with developing stable high‐voltage cathode materials are first discussed. Characterization techniques for understanding the composition and structure of the cathode–electrolyte interphase (CEI) are then introduced. Subsequently, recent developments in electrolyte design and interface modification for constructing a stable CEI are summarized. Finally, perspectives on future research trends for understanding and developing the high‐voltage CEI are discussed. This review can offer valuable guidance for understanding and designing the high‐voltage CEI, pushing forward the development of high‐energy‐density LMBs. [ABSTRACT FROM AUTHOR]

[Display omitted] Constructing artificial solid electrolyte interfaces (SEIs) to shape dendrite-free lithium (Li)-metal anodes remains challenges. Herein, we designed dynamic physical network (DPN) with abundant lithiophilic/anionphilic groups through tripartite hydrogen bonds (H-bonds), serving as artificial SEIs in high-loading NCM811-Li metal batteries. The formation and dissociation of DPN endowed by tripartite H-bonds under tension release during Li plating/stripping cycling skillfully balance the contradiction between mechanical robustness and deformability. Li O bonds between lithiophilic sites and Li ions, and extra H-bonds between hydroxyl and electrolyte anions, endow DPN with functions of homogenizing Li-ion flux and accelerating its desolvation, synergistically achieving the uniform Li-ion deposition and weakening the charge shielding. The artificial SEI enhanced Li-anode (DPN@Li) withstood repeated Li ions plating/stripping processes for over 1000 h, which is 5 times longer than pure Li-anodes, and maintained low overpotential at a high current density of 10 mA cm−2. DPN@Li-based NCM811 full cells deliver high specific capacities and outstanding cycle life over 3000 cycles. Further, DPN@Li possesses excellent electrochemical performance in the high active material loading (7.84 mg cm−2) and foldable pouch cells. This work provides a conceptual framework of DPN constructed by multiple weak intermolecular interaction for artificial SEI to shape anode performance, and achieves the idea with a facile manner and simple chemical substances to promote practical applications of LMBs. [ABSTRACT FROM AUTHOR]

Solid‐state lithium (Li) metal batteries (LMBs) have been developed as a promising replacement for conventional Li‐ion batteries due to their potential for higher energy. However, the current solid‐state electrolytes used in LMBs have limitations regarding mechanical and electrochemical properties and interfacial stability. Here, a fluorine (F)‐containing solid polymer electrolyte (SPE) having a bi‐continuous structure of F‐containing elastomers and plastic crystals is reported. The trifluoroethyl acrylate‐based SPE (T‐SPE) exhibits high ionic conductivity over 10−3 S cm−1, superior mechanical elasticity, and robust LiF‐rich interphases at both the Li metal anode and the LiNi0.83Mn0.06Co0.11O2 cathode. Full cells with thin T‐SPEs and low negative/positive capacity ratios below 0.5 at the high‐operating voltage of 4.5 V demonstrate a high specific energy of 538 Wh kganode+cathode+electrolyte−1 and maintain 393 Wh kg−1 at a high specific power of 804 W kganode+cathode+electrolyte−1. The F‐containing phase‐separated SPE system provides a powerful strategy for achieving high‐energy and ‐power solid‐state LMBs. [ABSTRACT FROM AUTHOR]

[Display omitted] Synthesis and electrochemical study of novel trifluorinated diethers, namely, α-methoxy-ω-(2,2,2-trifluoroethoxy)- alkanes, as potential candidates for new-generation electrolyte solvents for lithium-metal batteries are presented. The trifluoro diethers were tested in cell configurations implying cathodes with high nickel content and revealed Coulombic efficiencies exceeding 99.9% and specific discharge capacity retention up to 99% over 55 cycles for potentials up to 4.5 V. This study opens up new prospects in targeted design of organic ether molecules as lithium-metal batteries electrolyte components. [ABSTRACT FROM AUTHOR]

LiNO3 is a remarkable additive that can dramatically enhance the stability of ether‐based electrolytes at lithium metal anodes. However, it has long been constrained by its incompatibility with commercially used ester electrolytes. Herein, we correlated the fundamental role of entropy with the limited LiNO3 solubility and proposed a new low‐entropy‐penalty design that achieves high intrinsic LiNO3 solubility in ester solvents by employing multivalent linear esters. This strategy is conceptually different from the conventional enthalpic methods that relies on extrinsic high‐polarity carriers. In this way, LiNO3 can directly interact with the primary ester solvents and fundamentally alters the electrolyte properties, resulting in substantial improvements in lithium‐metal batteries with high Coulombic efficiency and cycling stability. This work illustrates the significance of regulating the solvation entropy for high‐performance electrolyte design. [ABSTRACT FROM AUTHOR]

The growing demand for high-performance next-generation lithium (Li)-based batteries has brought Li-metal anodes into the spotlight, due to their high theoretical capacity (3,860 mAh g-1) and low electrochemical potential (-3.04 V vs. SHE). However, the practical application of Li-metal anodes faces formidable challenges, primarily associated with dendritic Li growth resulting from non-uniform ion flux. Although previous studies utilizing carbonaceous materials having pores and lithiophilic atoms have demonstrated powerful performances, the complex process involving pore creation and doping with heteroatoms still has limitations in terms of cost-effectiveness. This study introduces a lithiophilic nitrogen (N)-doped three-dimensional (3D) porous carbon (NLC) by simply reusing and carbonizing NH2-functionalized lignin (NL), an eco-friendly biopolymer derived from waste wood generated during the pulping process. The NLC offers macro-porous spaces with a rich array of N-doped sites, capable of accommodating and guiding Li deposition to facilitate uniform Li growth. The results demonstrate the effectiveness of the NLC as the Li growth guiding layer in Li-metal batteries. A full cell incorporating the NLC as a Li growth guiding layer, with NCM811 as cathodes, exhibits a remarkable capacity of 145. 57 mAh g-1 even at a high C-rate of 5C and capacity retention of 90.3% (167 mAh g-1) after 150 cycles at 1C. These findings represent significant advancements compared to conventional Li-metal batteries.

Solid‐state electrolytes paired with lithium‐metal anodes is considered a next‐generation energy storage technology. However, the slow ionic transportation of the solid‐state electrolyte and the instability against the lithium‐metal anode impede their practical application. Here a cellulose separator modified with highly uniform boric oxide solid acid, contributing to a high transference number (0.75) and good ionic conductivity of 0.52 mS cm−1 due to the strengthened binding of the salt anions with this solid acid, is reported. Moreover, the boron ions with occupied interstitial sites can release free electrons to regulate the electrochemical dynamics of the electrolyte, in situ inducing the formation of Li2CO3/LiF‐rich heterostructured solid electrolyte interphase layer. The cellulose/B2O3‐based composite electrolyte paired with LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode and Li‐metal anode displays a specific capacity of 155 mAh g−1 with a capacity retention of 92% in 200 cycles. Additionally, this electrolyte paired with high‐mass‐loading NCM622 cathode (10 mg cm−2) in a pouch cell can be stably operated for 50 cycles with a capacity retention of over 90%. [ABSTRACT FROM AUTHOR]

The growing demand for high-performance next-generation lithium (Li)- based batteries has brought Li-metal anodes into the spotlight, due to their high theoretical capacity (3,860 mAh g-1) and low electrochemical potential (-3.04 V vs. SHE). However, the practical application of Li-metal anodes faces formidable challenges, primarily associated with dendritic Li growth resulting from non-uniform ion flux. Although previous studies utilizing carbonaceous materials having pores and lithiophilic atoms have demonstrated powerful performances, the complex process involving pore creation and doping with heteroatoms still has limitations in terms of costeffectiveness. This study introduces a lithiophilic nitrogen (N)-doped threedimensional (3D) porous carbon (NLC) by simply reusing and carbonizing NH2-functionalized lignin (NL), an eco-friendly biopolymer derived from waste wood generated during the pulping process. The NLC offers macroporous spaces with a rich array of N-doped sites, capable of accommodating and guiding Li deposition to facilitate uniform Li growth. The results demonstrate the effectiveness of the NLC as the Li growth guiding layer in Li-metal batteries. A full cell incorporating the NLC as a Li growth guiding layer, with NCM811 as cathodes, exhibits a remarkable capacity of 145. 57 mAh g-1 even at a high C-rate of 5C and capacity retention of 90.3% (167 mAh g-1) after 150 cycles at 1C. These findings represent significant advancements compared to conventional Li-metal batteries. [ABSTRACT FROM AUTHOR]

Due to high energy density and lower manufacturing cost, anode‐free lithium‐metal batteries (AFLMBs) are attracting increasing attention. The challenges for developing them lie in inferior Coulombic efficiency and short cycle life due to the highly reactive lithium metal. Herein, an electrochemical pre‐lithiation strategy is applied to layered oxide cathodes, specifically LiNiO2 and LiCoO2, aiming to provide an additional lithium source and understand the effect on the cathode structure for AFLMBs. The mechanism for accommodating the excess Li depends on the structural stability of the cathodes where LiNiO2 forms lithiated Li2NiO2 with the excess lithium in the crystalline lattice while the excess lithium in LiCoO2 forms a Li2O phase. More importantly, an optimal amount of Li excess is necessary to maintain decent cycle stability and specific capacity in AFLMB, with 40% excess Li for LiNiO2 and 150% for LiCoO2. While the pre‐lithiation process causes particle pulverization depending on the amount of Li excess, LiCoO2 offers a much better cycle performance than LiNiO2 with a promising capacity retention of 80% after 300 cycles in AFLMB (vs 76% after 100 cycles for 40% Li excess in LiNiO2). This study provides a promising avenue for developing tailor‐made layered oxide cathodes for AFLMBs. [ABSTRACT FROM AUTHOR]

Lithium metal is regarded as ideal anode material due to its high theoretical specific capacity and low electrode potential. However, the uncontrollable growth of lithium dendrites seriously hinders the practical application of lithium-metal batteries (LMBs). Among various strategies, carbon nanofiber materials have shown great potential in stabilizing the lithium-metal anode (LMA) due to their unique functional and structural characteristics. Here, the latest research progress on carbon nanofibers (CNFs) for LMA is systematically reviewed. Firstly, several common preparation techniques for CNFs are summarized. Then, the development prospects, strategies and the latest research progress on CNFs for dendrite-free LMA are emphatically introduced from the perspectives of neat CNFs and CNF-based composites. Finally, the current challenges and prospects of CNFs for stabilizing LMA are summarized and discussed. These discussions and proposed strategies provide new ideas for the development of high-performance LMBs.

[Display omitted] As a promising cathode material for high-performance lithium-ion batteries, olivine LiFe 1-x Mn x PO 4 (0 < x < 1, LFMP) combines the high safety of LiFePO 4 and the high energy density of LiMnPO 4. During the charge-discharge process, poor interface stability of active materials leads to capacity decay, which prevents its commercial application. Here, to stabilize the interface, a new electrolyte additive potassium 2-thienyl tri-fluoroborate (2-TFBP) is developed to boost the performance of LiFe 0.3 Mn 0.7 PO 4 at 4.5 V vs. Li/Li+. Specifically, after 200 cycles, the capacity retention remains at 83.78% in the electrolyte containing 0.2% 2-TFBP while the capacity retention without 2-TFBP addition is only 53.94%. Based on the comprehensive measurements results, the improved cyclic performance is attributed to that 2-TFBP has a higher highest occupied molecular orbit (HOMO) energy and its thiophene group can be electropolymerized above 4.4 V vs. Li/Li+ for generating uniform cathode electrolyte interphase (CEI) with poly-thiophene, which can stable materials structure and suppress the decomposition of electrolytes. Meanwhile, 2-TFBP both promotes the deposition/exfoliation of Li+ at anode-electrolyte interfaces and regulates Li deposition by K+ cations through the electrostatic mechanism. This work presents that 2-TFBP has a great application prospect as a functional additive for high-voltage and high-energy-density lithium metal batteries. [ABSTRACT FROM AUTHOR]

The application of Li‐metal‐anodes (LMA) can significantly improve the energy density of state‐of‐the‐art lithium ion batteries. Lots of new electrolyte systems have been developed to form a stable solid electrolyte interphase (SEI) films, thereby achieving long‐term cycle stability of LMA. Unfortunately, the common problem faced by these electrolytes is poor oxidation stability, which rarely supports the cycling of high‐voltage Li‐metal batteries (LMBs). In this work, a new single‐component solvent dimethoxy(methyl)(3,3,3‐trifluoropropyl) silane is proposed. The electrolyte composed of this solvent and 3 m LiFSI salt successfully supports the long‐term cycle stability of limited‐Li (50 µm)||high loading LiCoO2 (≈20 mg cm−2) cell at 4.6 V. Experiments and theoretical research results show that the outstanding performance of the electrolyte in high‐voltage LMBs is mainly attributed to its unique solvation structures and its great ability to build a highly stable and robust interphase on the surface of LMA and high‐voltage cathodes. Interestingly, this proposed electrolyte system builds a stable SEI film rich in LiF and Li3N on the surface of LMA by improving the two‐electron reduction activity of FSI− without adding LiNO3, the well‐known additive used for LMBs. The design idea of the proposed electrolyte can guide the development of high‐voltage LMBs. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: This work systematically reviews recent progresses in the applications of MOF‐derived materials modified 3D porous conductive framework as hosts for uniform lithium deposition in LMBs. A series of commonly used lithiophilic materials and several kinds of representative MOF‐derivation‐modified 3D hosts as lithium metal anode (LMA) are presented. Finally, the challenges and future development of employing MOF‐derived materials to modify the 3D porous conductive framework for LMA are included. [ABSTRACT FROM AUTHOR]

Lithium (Li) metal anodes have the highest theoretical capacity and lowest electrochemical potential making them ideal for Li metal batteries (LMBs). However, Li dendrite formation on the anode impedes the proper discharge capacity and practical cycle life of LMBs, particularly in carbonate electrolytes. Herein, we developed a reactive alternative polymer named P(St‐MaI) containing carboxylic acid and cyclic ether moieties which would in situ form artificial polymeric solid electrolyte interface (SEI) with Li. This SEI can accommodate volume changes and maintain good interfacial contact. The presence of carboxylic acid and cyclic ether pendant groups greatly contribute to the induction of uniform Li ion deposition. In addition, the presence of benzyl rings makes the polymer have a certain mechanical strength and plays a key role in inhibiting the growth of Li dendrites. As a result, the symmetric Li||Li cell with P(St‐MaI)@Li layer can stably cycle for over 900 h under 1 mA cm−2 without polarization voltage increasing, while their Li||LiFePO4 full batteries maintain high capacity retention of 96 % after 930 cycles at 1C in carbonate electrolytes. The innovative strategy of artificial SEI is broadly applicable in designing new materials to inhibit Li dendrite growth on Li metal anodes. [ABSTRACT FROM AUTHOR]

Enhancing the cut-off voltage of high-nickel layered oxide cathodes is an efficient way to obtain higher energy density of lithium-metal batteries (LMBs). However, the phase transition of the cathode materials and the uncontrolled decomposition of the electrolytes at high voltage can lead to irreversible dissolution of transition metal ions, which might cause the crossover effects on the lithium metal anodes. Nonetheless, the mechanism and electrolyte dependence of the crossover effects for Li metal anodes are still unclear. Herein, we investigate the crossover effects between LiNi0.8Mn0.1Co0.1O2 and Li-metal anode in two electrolyte systems. For ether-based electrolyte, its poor oxidation stability results in massive dissolution of transition metal ions, leading to dendrite growth on anode and rapid cells failure. Conversely, ester-based electrolyte exhibits good electrochemical performances at 4.5 V with little crossover effect. This study provides an idea for electrolyte systems selection for high-voltage LMBs, and verifies that the crossover effect should not be neglected in LMBs. [ABSTRACT FROM AUTHOR]

A lithium-metal composite is proposed, which includes a carbon-nitrogen modified stainless steel mesh (CNSSM) favoring homogeneous lithium-metal nucleation and growth of fresh and dense lithium deposits when employed as anode for lithium-metal batteries. This novel approach is able to overcome the usual drawbacks linked to the preexisting passivation layer at the surface of lithium. Instead, a favorable interphase with low resistivity is formed with the electrolyte, and the CNSSM modified lithium-metal composite (CNSSM-Li) results in low-voltage hysteresis (±24 mV) and allows stable and dendrite-free lithium electrodeposition. The performance of lithium-metal batteries demonstrates the outstanding capabilities of the novel CNSSM-Li electrode in promoting cell energy density and cycling stability. In addition, advanced X-ray nano-tomography is employed to characterize the composition and morphology changes of this electrode upon plating.

A lithium-metal composite is proposed, which includes a carbon-nitrogen modified stainless steel mesh (CNSSM) favoring homogeneous lithium-metal nucleation and growth of fresh and dense lithium deposits when employed as anode for lithium-metal batteries. This novel approach is able to overcome the usual drawbacks linked to the preexisting passivation layer at the surface of lithium. Instead, a favorable interphase with low resistivity is formed with the electrolyte, and the CNSSM modified lithium-metal composite (CNSSM-Li) results in low-voltage hysteresis (±24 mV) and allows stable and dendrite-free lithium electrodeposition. The performance of lithium-metal batteries demonstrates the outstanding capabilities of the novel CNSSM-Li electrode in promoting cell energy density and cycling stability. In addition, advanced X-ray nano-tomography is employed to characterize the composition and morphology changes of this electrode upon plating.

Due to the high reactivity between the lithium metal and traditional organic liquid electrolyte, the reaction of lithium metal electrode is usually uneven and there are also unexpected side reactions. Therefore, construction of a stable solid electrolyte interface (SEI) is highly essential to improve the performance of lithium metal anode. Herein, a sandwich-like gel polymer electrolyte (GPE) is accurately prepared by in-situ polymerization of Polyacrylonitrile (PAN) nanofiber membrane with trihydroxymethylpropyl trimethylacrylate (TMPTMA) and 1,6-hexanediol diacrylate (HDDA). The resulting GPE with a tightly cross-linked gel skeleton exhibits high ionic conductivity and electrochemical window of 5.6 V versus Li/Li+. In particular, the pretreatment of Li metal anode can improve the interfacial wettability, and the synergy of the chemically pretreated Li metal anode surface and the GPE can electrochemically in situ generate SEI with compositionally stable and fluorine-rich inorganic components. Owing to these unique advantages, the interfacial compatibility between the GPE and lithium metal is greatly improved. Meanwhile, the formed SEI can inhibit the formation of lithium dendrites, and decomposition of GPE would be alleviated. The assembled Li-FEC|GPE|LiFePO4 full cell shows a high initial discharge capacity of 157.1 mA h g−1, and maintains a capacity retention of 92.3% after 100 cycles at 0.2C.

The universal cathode crossover such as chemical and oxygen has been significantly overlooked in lithium metal batteries using high‐energy cathodes which leads to severe capacity degradation and raises serious safety concerns. Herein, a versatile and thin (≈25 μm) interlayer composed of multifunctional active sites was developed to simultaneously regulate the Li deposition process and suppress the cathode crossover. The as‐induced dual‐gradient solid‐electrolyte interphase combined with abundant lithiophilic sites enable stable Li stripping/plating process even under high current density of 10 mA cm−2. Moreover, X‐ray photoelectron spectroscopy and synchrotron X‐ray experiments revealed that N‐rich framework and CoZn dual active sites can effectively mitigate the undesired cathode crossover, hence significantly minimizing Li corrosion. Therefore, assembled lithium metal cells using various high‐energy cathode materials including LiNi0.7Mn0.2Co0.1O2, Li1.2Co0.1Mn0.55Ni0.15O2, and sulfur demonstrate significantly improved cycling stability with high cathode loading. [ABSTRACT FROM AUTHOR]

Challenges facing high‐voltage/high‐capacity cathodes, in addition to the longstanding problems pertinent to lithium (Li)‐metal anodes, should be addressed to develop high‐energy‐density Li‐metal batteries. This issue mostly stems from interfacial instability between electrodes and electrolytes. Conventional carbonate‐ or ether‐based liquid electrolytes suffer from not only volatility and flammability but also limited electrochemical stability window. Here, we report a nitrile electrolyte strategy based on concentrated nitrile electrolytes (CNEs) with co‐additives. The CNE consists of high‐concentration lithium bis(fluorosulfonyl)imide (LiFSI) in a solvent mixture of succinonitrile (SN)/acetonitrile (AN). The SN/AN solvent mixture is designed to ensure high oxidation stability along with thermal stability, which are prerequisites for high‐voltage Li‐metal cells. The CNE exhibits interfacial stability with Li metals due to the coordinated solvation structure. Lithium nitrate (LiNO3) and indium fluoride (InF3) are incorporated in the CNE as synergistic co‐additives to further stabilize solid‐electrolyte interphase (SEI) on Li metals. The resulting electrolyte (CNE + LiNO3/InF3) enables stable cycling performance in Li||LiNi0.8Co0.1Mn0.1 and 4.9 V‐class Li||LiNi0.5Mn1.5O4 cells. Notably, the Li||LiNi0.5Mn1.5O4 cell maintains its electrochemical activity at high temperature (100 °C) and even in flame without fire or explosion. [ABSTRACT FROM AUTHOR]

Polyethylene oxide (PEO)‐based polymer electrolytes with good flexibility and viscoelasticity, low interfacial resistance, and fabricating cost have caught worldwide attention, but their practical application is still hampered by the instability at high voltages and the low ionic conductivity (10−8 to 10−6 S cm−1). Herein, we rationally designed defects‐abundant Ga2O3 nanobricks as multifunctional fillers and constructed a PEO‐based organic‐inorganic electrolyte for lithium metal batteries. Due to the abundant O‐defects feature of Ga2O3 filler, this PEO‐based composite electrolyte not only broadens electrochemical stability window (over 5.3 V versus Li/Li+) but also in situ forms a Li–Ga alloy and solid electrolyte interphase (SEI) film during the cycling process causing a rapid diffusion of Li+ ions. The as‐prepared electrolyte has good interface compatibility with Li metal (without short‐circuiting over 500 h at 0.2 mA cm−2) and possesses superior high ionic conductivity. The assembled all‐solid‐state LiFePO4//Li cells attained an excellent cycling performance of 146 mAh g−1 over 100 cycles at 0.5 C. The XPS analysis reveals that Ga2O3 nanobricks can form in situ a Li−Ga alloy layer at the polymer/anode interface. This work shed a light on designing high ionic conductivity lithium alloys in the composite electrolyte, which can improve the electrochemical properties of PEO‐based polymer electrolytes. [ABSTRACT FROM AUTHOR]

Non‐flammable ionic liquid electrolytes (ILEs) are well‐known candidates for safer and long‐lifespan lithium metal batteries (LMBs). However, the high viscosity and insufficient Li+ transport limit their practical application. Recently, non‐solvating and low‐viscosity co‐solvents diluting ILEs without affecting the local Li+ solvation structure are employed to solve these problems. The diluted electrolytes, i.e., locally concentrated ionic liquid electrolytes (LCILEs), exhibiting lower viscosity, faster Li+ transport, and enhanced compatibility toward lithium metal anodes, are feasible options for the next‐generation high‐energy‐density LMBs. Herein, the progress of the recently developed LCILEs are summarised, including their physicochemical properties, solution structures, and applications in LMBs with a variety of high‐energy cathode materials. Lastly, a perspective on the future research directions of LCILEs to further understanding and achieve improved cell performances is outlined. [ABSTRACT FROM AUTHOR]

Metallic lithium is a fascinating anode for the next‐generation energy‐dense rechargeable batteries owing to the highest theoretical specific capacity and lowest electrochemical potential. Nevertheless, sluggish desolvation kinetics and notorious dendritic growth hinder its electrochemical performance and safe operation. Herein, an interlamellar Li+ conductor of Ag‐montmorillonite (AMMT) is proposed as an interfacial ion‐transport‐rectifying pump to induce the rapid and reversible plating/stripping of Li metal. Joint experimental and computational analyses reveal that the AMMT pump with negative charge layers and inherent channels can lower the desolvation energy and boost Li+ transport. The resultant Li anode is endowed with a low nucleation barrier (22.2 mV) and dendrite‐free features, leading to high plating/stripping density (8 mA cm‐2) and long lifespan (2500 h). Moreover, the corresponding Li||LiFePO4 batteries achieve a steady circulation (500 cycles@82%, 1 C) with a low N/P ratio. This strategy offers a fresh insight into constructing robust multifunctional electrolyte/Li anode interface for Li metal batteries. [ABSTRACT FROM AUTHOR]

Ion transport in composite electrodes plays a key role in the electrochemical performance of lithium‐metal batteries (LMBs), particularly at high current densities, and hence, some works have suggested the use of ionic conducting polymers as binders. Herein, in order to assess the importance of the type of ion conduction in binders, two poly(ionic liquid) polymers were analyzed as binders in LiFePO4 (LFP) cathodes: poly(lithium 1‐[3‐(methacryloyloxy)propylsulfonyl]‐1‐(trifluoromethane sulfonyl) imide) (PMTFSI−Li), and poly(diallyldimethylammonium bis(trifluoromethane sulfonyl)imide) (PDADMA−TFSI). Their functionalities allow modulating the individual transport of their counter‐ions, Li+ and TFSI−, respectively; in comparison with conventional PVDF binder. Thus, LFP−C‐Binder cathodes, namely C−PVDF, C−PDADMA−TFSI and C−PMTFSI−Li, were evaluated in LMBs. C−PMTFSI−Li exhibited the best performance reaching the theoretical specific capacity (170.3±0.8 mAh g−1) at C/10, an outstanding capacity at 10 C (100.6±0.5 mAh g−1), and long lifespan (>500 cycles at 1 C). C−PDADMA−TFSI showed good long‐term cycling and high performance at high C‐rate, while C−PVDF ended up fading before reaching 500 cycles. Surprisingly, it was observed that the presence of ionic binders into the cathode formulation influenced on Li0 metal deposition morphology, leading to a more homogeneous plating (specially PMTFSI−Li) in comparison with PVDF; and therefore, exhibiting a mitigation of mossy lithium growth. [ABSTRACT FROM AUTHOR]

The practical application of lithium (Li) metal battery is impeded by the Li dendrite growth and unstable solid electrolyte interphase (SEI) layer. Herein, an ultra‐stretchable and ionic conducting chemically crosslinked pressure‐sensitive adhesive (cPSA) synthesized via the copolymerization of 2‐ethylhexyl acrylate and acrylic acid with poly(ethyleneglycol)dimethacrylate as crosslinker (short for 70cPSA), is developed as both artificial SEI layer and solid polymer electrolyte (SPE) for stable Li‐metal electrode, enabling all‐solid‐state Li metal batteries with excellent cycling performance. As an artificial SEI layer, the 70cPSA‐modified electrodes exhibit excellent electrochemical performance in Li|70cPSA@Cu half cells and 70cPSA@Li|70cPSA@Li symmetric cells. In full cells with LiFePO4 (LFP) as cathode, the 70cPSA@Li|LFP cell exhibits stable cycling performance over 250 cycles. Utilized as SPE, the all‐solid‐state Li|SPE|LFP cell delivers excellent cycling stability with a capacity retention of 86% over 500 cycles. With high‐voltage LiNi0.8Mn0.1Co0.1O2 (NMC811) as cathode, the Li|SPE|NMC811 cell exhibits a discharge capacity of 124.3 mAh g−1 with a capacity retention of 71% after 200 cycles. The rational design of PSAs and investigation of their dual role for stable and safe Li‐metal batteries may shed a light on adhesive polymers for battery applications. [ABSTRACT FROM AUTHOR]

Concentration of electrolyte has significant effects on performances of rechargeable batteries. Previous studies mainly focused on concentrated electrolytes. So far, only several recipes on low‐concentration electrolytes were studied, performing enhanced performance in advanced rechargeable batteries. Here, based on common electrolyte components, a low‐concentration electrolyte composed of 0.2 M lithium hexafluorophosphate (LiPF6) solvated in fluoroethylene carbonate (FEC) and ethyl methyl carbonate (EMC) is employed for high‐voltage Li metal battery. The synergistic working mechanisms of introducing fluorine‐containing solvent in the solvated structure and low salt concentration effect are revealed, resulting in LiF‐rich, uniform, and robust solid electrolyte interphase layer and fewer unfavorable decomposition products. As a result, this low‐concentration electrolyte significantly enhances electrochemical performances of Li||Li symmetric cells and high‐voltage LiCoO2||Li batteries. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes (SPEs) are considered to be an important move to revive high-energy-density lithium-metal batteries due to their good flexibility and high safety. However, the low room-temperature ionic conductivity of SPEs has always been a stumbling block for their practical applications. Herein, a composite SPE has been fabricated by the cooperation of polyethylene oxide (PEO) and a type of natural nanoclay-halloysite nanotube (HNT) in a poly-(vinylidene fluoride) (PVDF) matrix. It is expected that the sticky PEO can improve the interfacial stability of the SPE and lithium foil, while the special structure and surface charge properties of the HNTs changed the coordination environment of lithium ions and facilitated Li+ running on highways along the HNT outer surface. The optimized SPE composite showed an outstanding room-temperature ionic conductivity of 2.45 × 10–4 S cm–1 and high ion transference number of 0.67 at 25 °C. A LiFePO4/SPE-H5/Li full battery retained a discharge capacity of 142 mAh g–1 after 200 cycles at a rate of 0.2 C (25 °C). In addition, SPE-H5 can also be used in a 4.3 V high voltage NCM/SPE-H5/Li battery due to its excellent electrochemical stability window (more than 5 V). This work also reveals that lower-cost natural clay minerals are excellent nanoceramic fillers in realizing sustainable high-energy-density energy storage. [ABSTRACT FROM AUTHOR]

Dissolution of lithium polysulfides (LiPSs) is essential for fast cathode kinetics, but detrimental for anode stability, especially under lean electrolyte conditions. In this work, the phase separation phenomenon between solvents with different polarities (tetramethyl sulfone [TMS] and dibutyl ether [DBE]) is utilized to enable the design of a dual‐phase electrolyte. High‐polarity, high‐density TMS–lithium bis(trifluoromethanesulfonyl)imide–ammonium trifluoroacetate as the cathode electrolyte strongly solvates LiPSs, which propel the sulfur redox reaction. Moreover, the composite of DBE and a polymeric ion conductor serves as the anode electrolyte. The addition of DBE in the anode side effectively prevents the crossover of corrosive species (LiPSs and ammonia trifluoroacetate), enabling a significant improvement in Li‐metal anode stability. The electrode‐specific dual‐phase electrolyte design provides electrochemical performance superior to conventional electrolytes. Without additional electrode engineering, pouch cells assemble with the dual‐phase electrolyte cycle under a lean electrolyte (4 µL mg−1) and low‐Li‐excess condition (N/P = 3) for 120 cycles. [ABSTRACT FROM AUTHOR]

Polyethylene oxide (PEO) electrolytes have been extensively researched in solid-state batteries due to their excellent interface compatibility, high flexibility, and ease of machining. However, its practical application is still hindered by low ionic conductivity (∼10−6 S cm−1 at room temperature) and a narrow electrochemical stability window. To settle these shortcomings, a PEO-based composite electrolyte enabled by active LiGaO 2 filler and 1-allyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide (AMIm-TFSI) ionic liquid is constructed for lithium metal batteries (LMBs). Benefiting from the synergistic effect of LiGaO 2 filler and AMIm-TFSI ionic liquid, this composite electrolyte not only enhances the ionic conductivity (2.08 × 10−3 S cm−1) and electrochemical window (5.2 V vs. Li+/Li) but also reduce the interfacial impedance. Furthermore, the Li//Li symmetric cells achieved an ultralong lithium deposition/stripping cycle over 1000 h at 0.1 mA cm−2. The assembled solid-state LiFePO 4 //Li cell exhibit superior rate capability (164.2, 158.5, 154.8, 148.6, 119.4 mAh g−1 at 0.1, 0.2, 0.5, 1, and 2 C, respectively) and excellent cycling stability (147.3 mAh g−1 after 300 cycles at 0.2C). The X-ray photoelectron spectroscopy (XPS) analysis reveals that the composite electrolytes in situ form an inorganic-rich solid electrolyte interface layer. This work provides guidance on designing superior organic-inorganic composite electrolytes for LMBs. [Display omitted] • PIL-CSE enabled by the synergistic effect of LiGaO 2 filler and IL for superior LMBs. • PIL-CSE achieved 2.08 × 10−3 S cm−1 at 60 °C and an electrochemical window >5.2 V. • XPS analysis reveals that PIL-CSE could in situ form an inorganic-rich SEI film. • The LiFePO 4 /PIL-CSE/Li exhibited a superior rate capability and cycling stability. [ABSTRACT FROM AUTHOR]

The uncontrollable formation of Li dendrites has become the biggest obstacle to the practical application of Li-metal anodes in high-energy rechargeable Li batteries. Herein, a unique LiF interlayer woven by millimeter-level, single-crystal and serrated LiF nanofibers (NFs) was designed to enable dendrite-free and highly efficient Li-metal deposition. This high-conductivity LiF interlayer can increase the Li+ transference number and induce the formation of 'LiF–NFs-rich' solid–electrolyte interface (SEI). In the 'LiF–NFs-rich' SEI, the ultra-long LiF nanofibers provide a continuously interfacial Li+ transport path. Moreover, the formed Li–LiF interface between Li-metal and SEI film renders low Li nucleation and high Li+ migration energy barriers, leading to uniform Li plating and stripping processes. As a result, steady charge–discharge in a Li//Li symmetrical cell for 1600 h under 4 mAh cm−2 and 400 stable cycles under a high area capacity of 5.65 mAh cm−2 in a high-loading Li//rGO–S cell at 17.9 mA cm−2 could be achieved. The free-standing LiF–NFs interlayer exhibits superior advantages for commercial Li batteries and displays significant potential for expanding the applications in solid Li batteries. [ABSTRACT FROM AUTHOR]

Electrolytes play a critical role in stabilizing highly reactive lithium‐metal anodes (LMAs) and high‐voltage cathodes for rechargeable lithium‐metal batteries (LMBs). Localized high concentration electrolytes (LHCEs) have achieved remarkable success in the context of LMBs. However, the state‐of‐the‐art LHCEs are based on LiFSI salt, which is prohibitively expensive. Here, the utility of low‐cost LiPF6 salt in localized saturated electrolytes (LSEs) with a series of solvents and diluents in LMBs with cobalt‐free LiNiO2 cathode is systematically explored. Experimental and theoretical analyses reveal that the unique solvation structure formed not only changes the distribution of solvents and anions but also alters the atom–atom distances within them, leading to different reduction and oxidation stabilities compared to low‐concentration electrolytes. In addition, LSEs help form LiF‐rich interphase layers on the LMA and LiNiO2 cathode, protecting the electrodes from degradation during cycling. Different LSEs also lead to differences in lithium plating morphology and impedance buildup during cycling, impacting the performance of LMBs. The solvent and diluent must be carefully selected for compatibility with a lithium salt when developing LHCEs and LSEs for LMBs. [ABSTRACT FROM AUTHOR]

Lithium-metal batteries (LMBs) are regarded as the most promising candidate for practical applications in portable electronic devices and electric vehicles because of their high capacity and energy density. However, the uncontrollable growth of lithium dendrite reduces its cycling ability and even causes a severe safety concern, which impedes the development of the technology. Although great efforts have been devoted to solving the lithium dendrite issue in recent years, the contradiction between the high cost of thin Li foil and the severe safety hazard of excess Li still exists. This is precisely the factor that inspired the development of anode-free lithium-metal batteries (AFLMBs). Compared to lithium-metal batteries, AFLMBs with a zero-excess Li anode possess an incredible, conceivable, and specific energy. Additionally, because the use of metal lithium is limited, the battery manufacturing will be safer and simpler, leading to a significant decrease in cost. However, comprehensive reviews on anode-free batteries are rare. Therefore, in this review, we aim to explain the essential development factors influencing the cycle life, energy density, cost, and working mechanism of anode-free batteries. We summarize different strategies to improve the cycling stability of AFLMBs, and we discuss the application of anode-free electrodes in other electrochemical energy storage systems. Moreover, it is believed that the combination of modification techniques, including electrolytes and current collectors, and the application protocols will be the most important solution for future anode-free batteries. [ABSTRACT FROM AUTHOR]

Designing current collectors and constructing efficient artificial solid electrolyte interphase (SEI) layers are promising strategies for achieving dendrite-free Li deposition and practical applications in Li metal batteries (LMBs). Electrodeposition is advantageous for large-scale production and allows the direct formation of current collectors without binders, making them immediately usable as electrodes. In this study, an adherent Cu 2 S thin-layer on Cu foil is synthesized through anodic electrodeposition from a Na 2 S solution in a one-step process, followed by the generation of Li 2 S layers as artificial SEI layers via a conversion reaction (3DLi 2 S-Cu foil). The Li 2 S layers move from the 3D Cu surface to the deposited Li surface, facilitating uniform and dense Li deposition. The 3DLi 2 S-Cu foil structure demonstrates stable cycling performance over 350 cycles in an asymmetric cell, with a capacity of 1 mAh cm -2 at 1 mA cm -2 . Moreover, symmetric cells with 5 mAh cm -2 of deposited Li exhibit a stable cycle life for over 1200 h. When paired with commercial LiFePO 4 (LFP), the full cells show substantially enhanced cyclability, regardless of the amount of deposited Li. This study provides new insights into the construction of artificial SEIs for facilitating commercial applications., (© 2024 Wiley‐VCH GmbH.)

The intrinsic reactivity of lithium (Li) toward ambient air, combined with insufficient cycling stability in conventional electrolytes, hinders the practical adoption of Li metal anodes in rechargeable batteries. Here, a bilayer interphase for Li metal is introduced to address both its susceptibility to corrosion in ambient air and its deterioration during cycling in carbonate electrolytes. Initially, the Li metal anode is coated with a conformal bottom layer of polysiloxane bearing methacrylate, followed by further grafting with poly(vinyl ethylene carbonate) (PVEC) to enhance anti-corrosion capability and electrochemical stability. In contrast to single-layer applications of polysiloxane or PVEC, the bilayer design offers a highly uniform coating that effectively resists humid air and prevents dendritic Li growth. Consequently, it demonstrates stable plating/stripping behavior with only a marginal increase in overpotential over 200 cycles in carbonate electrolytes, even after exposure to ambient air with 46% relative humidity. The design concept paves the way for scalable production of high-voltage, long-cycling Li metal batteries., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

Lithium‐metal batteries (LMBs) capable of operating stably at high temperature application scenarios are highly desirable. Conventional lithium‐ion batteries could only work stably under 60 °C because of the thermal instability of electrolyte at elevated temperature. Here we design and develop a thermal stable electrolyte based on stable solvation structure using multiple ion–dipole interactions. The strong coordination in solvated structure of electrolyte defines the Li deposition behaviour and the evolution of solid electrolyte interphase at high temperature, which is important to achieve high Li Coulombic efficiency and avoid Li dendritic growth. For high mass loading LiFePO4‐Li cells, the cells at 60 °C with conventional electrolyte easily run into failures, but the cells with our electrolyte at 90 °C and 100 °C could cycle more than 120 and 50 cycles respectively. This work provides new insight into electrolyte design and contributes to the development of high temperature LMBs. [ABSTRACT FROM AUTHOR]

Lithium metal is regarded as "holy grail" in the secondary rechargeable batteries. However, irregular Li deposition and dead lithium during the plating/striping process lead to serious safety issues and rapid capacity decay. The low conductivity of matrix and inhomogeneous ion transfer result in the growth of lithium dendrite and thus the low coulombic efficiency. Here, the authors propose to solve this issue by constructing highly conductive matrix with regulated charge transfer. A low surface tension (LST) strategy is adopted to construct ultrathin reduced graphene oxide (UrGO) to storage Li. The ultrathin and loose structure promise UrGO with high conductivity and the uniformly distributed residue oxygen‐containing groups helps to induce the uniform deposition of lithium due to the improved affinity to Li. The obtained UrGO with high conductivity shows a low lithium nucleation overpotential. The UrGO@Li electrode reveals an outstanding electrochemical stability with a high coulombic efficiency of 98.5% for over 300 cycles. The good performances of full cell also indicate the successful design of the UrGO matrix and the LST strategy provides a new vision for designing highly conductive graphene‐based porous materials. [ABSTRACT FROM AUTHOR]

As emerging eutectic mixtures, deep eutectic electrolytes (DEEs) show unique properties for Li‐metal batteries (LMBs). However, the limited choice and inferior electrode compatibility hinder their further development in LMBs. Herein, we report a new 1,2‐dimethylimidazole (DMIm)‐based deep eutectic gel polymer electrolyte induced by Li−N interaction. We demonstrate that incorporating electron‐withdrawing polyvinylidene difluoride (PVDF) polymer into the DMIm‐based DEE changes the coordination environment of Li+ ions, leading to a high transference number of Li+ ions (0.65) and superior interface stability between the electrolyte and Li anode. The deep eutectic gel polymer electrolyte exhibits excellent non‐flammability, high ionic conductivity (1.67 mS cm−1 at 30 °C), and high oxidation voltage (up to 4.35 V vs. Li/Li+). The Li||LFP cell based on the newly developed deep eutectic gel polymer electrolyte can achieve superior long‐term cycling stability at a wide range of rates. [ABSTRACT FROM AUTHOR]

Uneven lithium deposition and uncontrollable dendrite growth limit the development and progress of lithium-metal batteries (LMBs). Here, we developed an appropriate strategy to prevent the damage of Li dendrites by introducing inorganic oxide solid electrolyte layers (Li1.3Al0.3Ti1.7(PO4)3, LATP) on both sides of a polypropylene separator (PP). The inorganic coating layers, which comprise close-packed LATP solid electrolyte particles, afford a firm and uniform microstructure for the hybrid separator. At a current density (0.25 mA cm−2), the lithium symmetric batteries composed of the LATP/PP separator exhibit a long cycle life of over 1600 h in the 1 M LiTFSI-DOL/DME electrolyte. Furthermore, the LiFePO4||LATP/PP||Li cell presents a prominent performance and delivers an average charge capacity of 151 mAh g−1 at 1 C. This can be attributed to the unique characteristics of the LATP/PP separator, as it not only has outstanding mechanical strength and thermal stability, but also possesses high ionic conductivity, which effectively enhances the rate capacity to improve the safety of LMBs. LATP/PP separator is prepared by the coating method, and the Li symmetric batteries can cycle more than 1600 h in the 1 M LiTFSI-DOL/DME, which show an outstanding electrochemical performance. [ABSTRACT FROM AUTHOR]

Despite their potential as high‐energy‐density lithium battery electrodes, Li metals are still far from practical use mainly due to their insufficient electrochemical reliability. Here, a cholesteric liquid crystalline (cLC) cellulose nanocrystal (CNC) nanomembrane as a natural material‐based mechanically robust and precisely defined ion channel strategy for sustainable Li metal electrodes is demonstrated. The cLC‐CNC nanomembrane (1 µm) is designed to achieve a self‐assembled ordered nanoporous structure with optimal tortuosity. This well‐defined cLC structure and high mechanical modulus of CNC, which are difficult to attain with traditional synthetic materials, allow facile/uniform Li‐ion flux toward Li metal electrodes, and simultaneously prevent Li dendrite growth and mitigate volume expansion of the Li metal during Li plating/stripping cycling. Driven by these viable roles of the cLC‐CNC nanomembrane, Li metal full cells (consisting of thin Li metal anodes (20 µm) and high‐capacity LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes (3.8 mAh cm–2), capacity excess of the Li metal over the NCM811 = 1.0) exhibit high energy density (890 Wh Lcell–1) along with stable cycling retention, which lie far beyond those achievable with previously reported Li protective layers. [ABSTRACT FROM AUTHOR]

The lifespan of practical lithium (Li)‐metal batteries is severely hindered by the instability of Li‐metal anodes. Fluorinated solid electrolyte interphase (SEI) emerges as a promising strategy to improve the stability of Li‐metal anodes. The rational design of fluorinated molecules is pivotal to construct fluorinated SEI. Herein, design principles of fluorinated molecules are proposed. Fluoroalkyl (−CF2CF2−) is selected as an enriched F reservoir and the defluorination of the C−F bond is driven by leaving groups on β‐sites. An activated fluoroalkyl molecule (AFA), 2,2,3,3‐tetrafluorobutane‐1,4‐diol dinitrate is unprecedentedly proposed to render fast and complete defluorination and generate uniform fluorinated SEI on Li‐metal anodes. In Li–sulfur (Li−S) batteries under practical conditions, the fluorinated SEI constructed by AFA undergoes 183 cycles, which is three times the SEI formed by LiNO3. Furthermore, a Li−S pouch cell of 360 Wh kg−1 delivers 25 cycles with AFA. This work demonstrates rational molecular design principles of fluorinated molecules to construct fluorinated SEI for practical Li‐metal batteries. [ABSTRACT FROM AUTHOR]

Lithium‐metal batteries have attracted much attention due to their high energy density. However, the hydrolysis of LiPF6 leads to uncontrollable Li dendrites growth and fast capacity fading. Herein, a hydrophobic Li+‐solvated structure is designed by inducing the hexafluoroisopropyl acrylate into the electrolyte system. Due to the alkene groups and non‐polar perfluorocarbon (−CF2CF2CF3) chain, a hydrophobic surface around Li‐ion solvated aggregates can be obtained to protect the LiPF6 against the attack from trace H2O. Moreover, the additive could also help to form an organic solid electrolyte interphase with rich polar C−F bonds, which can capture Li ions to restrain the dendrite growth. Therefore, the Li||Li symmetric cells show a stable cycling performance up to 500 h at a current density of 1 mA cm−2. The Li||LiNi0.6Co0.2Mn0.2O2 cells show good cycling stability, exhibiting a specific capacity of 111 mAh g−1 at 1 C with a capacity retention of 74 % after 200 cycles. [ABSTRACT FROM AUTHOR]