RESUMO
The activation of trace LiNO3 additives in high-concentration electrolytes is achieved by BF3 due to its Lewis acidity. This advanced electrolyte can promote the decomposition of LiNO3 into Li3N, attaining enhanced cycle reversibility of lithium anodes, which broadens the application of LiNO3 additives.
RESUMO
The increasing demand for energy storage is calling for improvements in cathode performance. In traditional layered cathodes, the higher energy of the metal 3d over the O 2p orbital results in one-band cationic redox; capacity solely from cations cannot meet the needs for higher energy density. Emerging anionic redox chemistry is promising to access higher capacity. In recent studies, the low-lying O nonbonding 2p orbital was designed to activate one-band oxygen redox, but they are still accompanied by reversibility problems like oxygen loss, irreversible cation migration, and voltage decay. Herein, by regulating the metal-ligand energy level, both extra capacities provided by anionic redox and highly reversible anionic redox process are realized in NaCr1- y Vy S2 system. The simultaneous cationic and anionic redox of Cr/V and S is observed by in situ X-ray absorption near edge structure (XANES). Under high d-p hybridization, the strong covalent interaction stabilizes the holes on the anions, prevents irreversible dimerization and cation migration, and restrains voltage hysteresis and voltage decay. The work provides a fundamental understanding of highly reversible anionic redox in layered compounds, and demonstrates the feasibility of anionic redox chemistry based on hybridized bands with d-p covalence.
RESUMO
A transformative concept of solid electrochemical corrosion has been put forward, in which solid-state electrolyte LiPON has been applied to replace the liquid one to prelithiate graphite with Li-metal. Thus, high prelithiation efficiency and low polarization of the treated anode can be obtained, with a unique mosaic structure left at the surface.