Self-Purifying Primary Solvation Sheath Enables Stable Electrode–Electrolyte Interfaces for Nickel-Rich Cathodes

Abstract

Herein, we optimize the primary solvation sheath to investigate the fundamental correlation between battery performance and electrode− electrolyte interfacial properties through electrolyte solvation chemistry. Experimental and theoretical analyses reveal that the primary solvation sheath with a self-purifying feature can "positively" scavenge both the HF and PF 5 (hydrolysis of ion-paired LiPF 6 ), stabilize the PF 6 anion-derived electrode− electrolyte interfaces, and thus boost the cycling performances. Being attributed with these superiorities, the NCM811//Li Li metal battery (LMB) with the electrolyte containing the optimized solvation sheath delivers 99.9% capacity retention at 2.5 C after 250 cycles. To circumvent the impact of excess Li content of Li metal on the performance of NCM811 cathode, the as-fabricated NCM811//graphite Li ion battery (LIB) also delivers a high-capacity retention of 90.1% from the 5th to the 100th cycle at 1 C. This work sheds light on the strong ability of the primary solvation sheath to regulate cathode interfacial properties.

Electrolytes Design for Extending the Temperature Adaptability of Lithium‐Ion Batteries: from Fundamentals to Strategies

“…Electrolytes in batteries influence the solvation structure and transport process of Li + , as well as the formation of inter-facial film and their properties during the charge/discharge process. [52][53][54] The properties of electrolytes such as viscosity and conductivity vary with temperature changes, quantifying how Li + cations transport. In addition, the interfacial products between the electrolyte and electrode change with temperature.…”