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.

Lithium-sulfur batteries, as one of the most promising next-generation batteries, attract tremendous attentions due to their high energy density and low cost. However, their practical application is hindered by their short cycling life and low volumetric capacity. Herein, compact, flexible, and free-standing films with a sandwich structure are designed simply by vacuum filtration, in which nanosulfur is homogenously coated by graphene and poly(3,4-ethylene-dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). This unique hierarchical structure not only provides a highly conductive network and intimate contacts between nanosulfur and graphene/PEDOT:PSS for effective charge transportation, but also offers synergistic physical restriction and chemical confinement of dissoluble intermediate lithium polysulfides during electrochemical processes. Therefore, these conductive compact films, used directly as cathodes, show the highest reversible volumetric capacity of 1432 Ah L at 0.1 C and 1038 Ah L at 1 C, and excellent cycling stability with a minimal decay rate of 0.04% per cycle over 500 cycles at 1 C. Meanwhile, remarkable rate performance with a high capacity of 701 mAh g at 4 C is also achieved. Soft-packaged batteries based on this flexible cathode are further fabricated and demonstrate excellent mechanical and electrochemical properties with little capacity decay under folded state, highlighting the practical application of our deliberately designed electrode in a flexible power system.

Synthesis of ultrasmall metal-organic framework (MOF) nanoparticles has been widely recognized as a promising route to greatly enhance their properties but remains a considerable challenge. Herein, we report one facile and effective spatially confined thermal pulverization strategy to successfully transform bulk Co-MOF particles into sub-5 nm nanocrystals encapsulated within N-doped carbon/graphene (NC/G) by using conducting polymer coated Co-MOFs/graphene oxide as precursors. This strategy involves a feasible mechanism: calcination of Co-MOFs at proper temperature in air induces the partial thermal collapse/distortion of the framework, while the uniform coating of a conducting polymer can significantly improve the decomposition temperature and maintain the component stability of Co-MOFs, thus leading to the pulverization of bulk Co-MOF particles into ultrasmall nanocrystals without oxidation. The pulverization of Co-MOFs significantly increases the contact area between Co-MOFs with electrolyte and shortens the electron and ion transport pathway. Therefore, the sub-5 nm ultrasmall MOF nanocrystals-based composites deliver an ultrahigh reversible capacity (1301 mAh g at 0.1 A g), extraordinary rate performance (494 mAh g at 40 A g), and outstanding cycling stability (98.6% capacity retention at 10 A g after 2000 cycles), which is the best performance achieved in all reported MOF-based anodes for lithium-ion batteries.

The development of ultrahigh-voltage lithium metal batteries is one of the most promising ways to increase the energy density. However, commercial ethylene carbonate (EC)-based electrolytes have poor compatibility with both...