Lithium (Li) metal has been pursued as “Holy Grail” among various anode materials due to its high specific capacity and the lowest reduction potential. However, uncontrolled growth of Li dendrites and extremely unstable interfaces during repeated Li plating/stripping ineluctably plague the practical applications of Li metal batteries. Herein, an artificial protective layer with synergistic soft–rigid feature is constructed on the Li metal anode to offer superior interfacial stability during long‐term cycles. By suppressing random Li deposition and the formation of isolated Li, such a protective layer enables a dendrite‐free morphology of Li metal anode and suppresses the depletion of Li metal and electrolyte. Additionally, sufficient ionic conductivity is guaranteed through the synergy between soft and rigid structural units that are uniformly dispersed in the layer. Dendrite‐free and dense Li deposition, as well as a greatly reduced interfacial resistance after cycling, is achieved owing to the stabilized interface, accounting for significantly prolonged cycle life of Li metal batteries. This work highlights the ability of synergistic organic/inorganic protective layer in stabilizing Li metal anode and provides fresh insights into the energy chemistry and mechanics of anode in a working battery.

The persistent efforts to reveal the formation and evolution mechanisms of solid electrolyte interphase (SEI) are of fundamental significance for the rational regulation. In this work, through combined theoretical and experimental model investigations, we elucidate that the electric double layer (EDL) chemistry at the electrode/electrolyte interface beyond the thermodynamic stability of electrolyte components predominately controls the competitive reduction reactions during SEI construction on Li metal anode. Specifically, the negatively‐charged surface of Li metal will prompt substantial cation enrichment and anion deficiency within the EDL. Necessarily, only the species participating in the solvation shell of cations could be electrostatically accumulated in proximity of Li metal surface and thereafter be preferentially reduced during sustained dynamic cycling. Incorporating multi‐valent cation additives to more effectively drag the favorable anionic SEI enablers into EDL is validated as a promising strategy to upgrade the Li protection performance. The conclusions drawn herein afford deeper understandings to bridge the EDL principle, cation solvation, and SEI formation, shedding fresh light on the targeted regulation of reactive alkali metal interfaces.

The lithium metal anode is regarded as apromising candidate in next-generation energy storage devices.L ithium nitrate (LiNO 3 )i sw idely applied as an effective additive in ether electrolyte to increase the interfacial stability in batteries containing lithium metal anodes.However,because of its poor solubility LiNO 3 is rarely utilized in the high-voltage window provided by carbonate electrolyte.D issolution of LiNO 3 in carbonate electrolyte is realized through an effective solvation regulation strategy.L iNO 3 can be directly dissolved in an ethylene carbonate/diethyl carbonate electrolyte mixture by adding trace amounts of copper fluoride as ad issolution promoter.L iNO 3 protects the Li metal anode in aw orking high-voltage Li metal battery.W hen aL iNi 0.80 Co 0.15 Al 0.05 O 2 cathode is paired with aL im etal anode,a ne xtraordinary capacity retention of 53 %i sa chieved after 300 cycles (13 % after 200 cycles for LiNO 3 -free electrolyte) and av ery high average Coulombic efficiency above 99.5 %i sa chieved at 0.5 C. The solvation chemistry of LiNO 3 -containing carbonate electrolyte may sustain high-voltage Li metal anodes operating in corrosive carbonate electrolytes.Securing long battery life between charges is al ong-term pursuit in mobile energy storage devices with high energy density. [1] Lithium-ion batteries-one of the most mature and widely adopted energy storage devices-are now approaching at heoretical energy density limit. Therefore,a lternative strategies are needed to meet the increasing demands of portable electronics,e lectric vehicles,a nd grid-scale energy storage. [2] Lithium metal batteries (LMBs), which contain ahigh-voltage cathode and Li metal anode,outperform other candidates because they possess an ultrahigh theoretical specific capacity (3860 mAh g À1 )a nd the lowest reduction potential (À3.04 Vv s. standard hydrogen electrode (SHE)) among Li metal anodes. [3,4] Nevertheless,s evere problems impede the practical application of high-voltage LMBs-and particularly Li metal anodes,w hich first appeared in the 1970s. [5] Instead of forming uniform deposits,L it ends to adopt dendritic morphology during electrodeposition because of non-uniform current/ion distributions. [6] Li dendrites commonly lead to the formation of unstable solid electrolyte interfaces (SEI), low Coulombic efficiency (CE) because of high chemical reactivity,a nd even severe safety hazards when the separator is penetrated. [7,8] Theu nstable SEI can further aggravate dendrite growth, finally leading to rechargeable batteries with apoor lifespan. Therefore,stabilizing the Li interface is required to ensure that LMBs are practically viable.Spontaneous reactions between Li metal and electrolyte generate SEI, [7] and regulating the properties of the SEI by altering the electrolyte components is af acile and feasible approach. Lithium nitrate (LiNO 3 ), with ah igh solubility in ether solvent (typically 5wt% in dimethoxyethane and 1,3-dioxolane) is regarded as ac ritical electrolyte additive in lithium-sulfur (Li-S)...

The lithium–sulfur (Li–S) battery is regarded as a promising high‐energy‐density battery system, in which the dissolution–precipitation redox reactions of the S cathode are critical. However, soluble Li polysulfides (LiPSs), as the indispensable intermediates, easily diffuse to the Li anode and react with the Li metal severely, thus depleting the active materials and inducing the rapid failure of the battery, especially under practical conditions. Herein, an organosulfur‐containing solid electrolyte interphase (SEI) is tailored for the stabilizaiton of the Li anode in Li–S batteries by employing 3,5‐bis(trifluoromethyl)thiophenol as an electrolyte additive. The organosulfur‐containing SEI protects the Li anode from the detrimental reactions with LiPSs and decreases its corrosion. Under practical conditions with a high‐loading S cathode (4.5 mgS cm−2), a low electrolyte/S ratio (5.0 µL mgS−1), and an ultrathin Li anode (50 µm), a Li–S battery delivers 82 cycles with an organosulfur‐containing SEI in comparison to 42 cycles with a routine SEI. This work provokes the vital insights into the role of the organic components of SEI in the protection of the Li anode in practical Li–S batteries.

Lithium–sulfur (Li–S) batteries promise great potential as high‐energy‐density energy‐storage devices due to their ultrahigh theoretical energy density of 2600 Wh kg−1. Evaluation and analysis on practical Li–S pouch cells are essential for achieving actual high energy density under working conditions and affording developing directions for practical applications. This review aims to afford a comprehensive overview of high‐energy‐density Li–S pouch cells regarding 7 years of development and to point out further research directions. Key design parameters to achieve actual high energy density are addressed first, to define the research boundaries distinguished from coin‐cell‐level evaluation. Systematic analysis of the published literature and cutting‐edge performances is then conducted to demonstrate the achieved progress and the gap toward practical applications. Following that, failure analysis as well as promotion strategies at the pouch cell level are, respectively, discussed to reveal the unique working and failure mechanism that shall be accordingly addressed. Finally, perspectives toward high‐performance Li–S pouch cells are presented regarding the challenges and opportunities of this field.