In Situ Generation of HNO 3 via Lithium Nitrate and Fluorobenzene to Boost Lithium Battery Performance

Abstract It is crucial to improve the stability of the electrolyte with the lithium metal anode as well as the nickel‐rich cathode, which is a key to suppressing side reactions and extending the lifetime of high‐voltage lithium battery. In this work, a synergistic approach by combining fluorobenzene diluents and lithium nitrate is employed to in situ generate trace amount of nitric acid as well as enable weakly solvation structure of lithium ions, which effectively promoted the formation of inorganic‐rich solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI). The HF generation and transition metal dissolution are successfully suppressed. The stability of the LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) cathode and lithium plating/stripping efficiency at the anode are greatly enhanced. As a result, the Li||NCM811 battery demonstrated remarkable capacity retention of 80% after 360 cycles at 4.6 V. Similarly, the Graphite||NCM811 battery exhibited impressive capacity retention up to 80% even after 800 cycles at 4.4 V with lean electrolyte. This study provides new insights into the electrolyte development for high‐voltage lithium batteries and highlights the synergistic mechanism of fluorobenzene and lithium nitrate additives, which shows great potential for developing efficient, reliable, and environmentally friendly energy storage electrolytes.