Lithium‐metal batteries (LMBs) are considered as promising next‐generation batteries due to their high energy density. However, commercial carbonate electrolytes cannot be used in LMBs due to their poor compatibility with the lithium‐metal anode and detrimental hydrogen fluoride (HF) generation by lithium hexafluorophosphate decomposition. By introducing lithium nitrate additive and a small amount of tetramethylurea as a multifunctional cosolvent to a commercial carbonate electrolyte, NO3−, which is usually insoluble, can be introduced into the solvation structure of Li+ to form a conductive and stable solid electrolyte interface. At the same time, HF generation is suppressed by manipulating the solvation structure and a scavenging effect. As a result, the Coulombic efficiency (CE) of Li||Cu half cells using the designed carbonate electrolyte can reach 98.19% at room temperature and 96.14% at low temperature (−15 °C), and Li||LiFePO4 cells deliver a high capacity retention of 94.9% with a high CE of 99.6% after 550 cycles. This work provides a simple and effective way to extend the use of commercial carbonate electrolytes for next‐generation battery systems.

Wearable electronics require lightweight and flexible batteries, of which lithiumsulfur (Li-S) batteries are of great interest due to their high gravimetric energy density. Nevertheless, flexible Li-S batteries have unsatisfactory electrochemical performance owing to electrode fracture during repeated bending, the volume change of sulfur species and the severe shuttle effect. Binders play essential roles in these batteries but have always lacked attention. Herein, a self-healing polyvinylpyrrolidone-polyethyleneimine (PVP-PEI) binder cross-linked by hydrogen bonds, which also regulates polysulfide redox kinetics, is reported. The dynamic hydrogen-bonding networks repair the cracks and ensure the integrity of the electrode while numerous polar groups such as CO and -NH 2 suppress the shuttle effect by immobilizing polysulfides. Therefore, Li-S batteries with the PVP-PEI binder exhibit excellent cycling stability (a capacity decay rate of 0.0718% per cycle at 1 C after 450 cycles), an outstanding areal capacity of 7.67 mAh cm −2 even under a high sulfur loading (7.1 mg cm −2 ) and relatively lean electrolyte conditions (E/S ratio = 8 µL mg −1 ). Flexible Li-S pouch cells using the PVP-PEI binder show a stable performance for 140 cycles and a favorable capacity retention of over 95% after 2800 bending cycles, confirming its application potential in high-performance flexible Li-S batteries.

urgent need to exploit "'beyond LIBs"' that can meet this demand. [6][7][8][9][10] For the anode side, the lightweight (0.534 g cm −3 ), low electrochemical redox potential (−3.04 V vs standard hydrogen electrode), and high theoretical capacity (3860 mAh g −1 ) of lithium make it an attractive candidate for the anode as an alternative to graphite. [1,3,[11][12][13][14][15] For the cathode side, in addition to exploring materials with a high capacity such as sulfur or oxygen, which bring additional problems caused by new materials, increasing the cut-off voltage is the most effective way to boost the energy density. [3,4,6] Therefore, lithium metal batteries (LMBs) coupled with a high-voltage cathode are highly expected to be the nextgeneration battery systems.However, the development of electrolytes has always lagged far behind electrodes and enormous attention is expected to the development of electrolytes compatible with both the cathodes and anodes. Various electrolyte recipes have demonstrated great performance and among them, carbonate-based and ether-based electrolytes are the most used electrolytes. Despite that much higher Coulombic efficiency could be realized in ether-based electrolytes due to the formation of an elastic interface that helps withstand large volume changes of lithium during cycling, [16] the cut-off voltages of the full cells are usually no more than 4.6 V even in high concentration electrolytes (HCEs) and localized high concentration electrolytes (LHCEs) because of the limited intrinsic electrochemical window of ethers, hindering their use in high-voltage battery systems. [6,[17][18][19][20][21][22] Moreover, the flash points of ethers are relatively low and gas generation occurs in ether-based electrolytes at a high voltage of ≈4.6 V even in a LHCE, [23,24] making it unsuitable for very high voltage operation. Therefore, carbonate electrolytes with good oxidative stability and high flash points that have long been used in commercial LIBs are the most cost-effective and suitable to be adopted in high-voltage LMBs. [25] However, conventional ethylene carbonate (EC)-based electrolytes are not stable against the lithium metal anode, forming a low-quality interface on it that leads to the uncontrolled growth of lithium, which aggravates the consumption of the electrolyte and eventually leads to battery failure. [6,7,16] These EC-based electrolytes also undergo a series of side reactions with Ni-rich cathodes, including nucleophilic and dehydrogenation reactions, and ring-opening. [4,6] The decomposition of lithium hexafluorophosphate (LiPF 6 ), the mainstream salt, is another critical issue of carbonate electrolytes because it Lithium metal batteries (LMBs) are considered promising candidates for nextgeneration battery systems due to their high energy density. However, commercialized carbonate electrolytes cannot be used in LMBs due to their poor compatibility with lithium metal anodes. While increasing cut-off voltage is an effective way to boost the energy density of LMBs, conventional et...