Enhancing\nElectrochemical Performances of Rechargeable\nLithium-Ion Batteries via Cathode Interfacial Engineering

Abstract

Lithium-ion\nbatteries (LIBs) have transformed modern electronics\nand rapidly advancing electric vehicles (EVs) due to their high energy\nand power densities, cycle-life, and acceptable safety. However, the\ncomprehensive commercialization of EVs necessitates the invention\nof LIBs with much enhanced and stable electrochemical performances,\nincluding higher energy/power density, cycle-life, and operational\nsafety, but at a lower cost. Herein, we report a simple method for\nimproving the high-voltage (up to 4.5 V) charge capability of LIBs\nby applying a Li⁺-ion-conducting artificial cathode–electrolyte\ninterface (Li⁺-ACEI) on the state-of-the-art cathode, LiCoO₂ (LCO). A superionic ceramic single Li⁺ ion conductor,\nlithium aluminum germanium phosphate (Li_1.5Al_0.5Ge_1.5(PO₄)₃, LAGP), has been used\nas a novel Li⁺-ACEI. The application of Li⁺-ACEI\non LCO involves a scalable and straightforward wet chemical process\n(sol–gel method). Cycling performance, including high voltage\ncharge, of bare and LAGP-coated cathodes has been determined against\nthe most energy-dense anode (lithium, Li metal) and state-of-the-art\ncarbonate-based organic liquid electrolyte (OLE). The application\nof an LAGP-based Li⁺-ACEI on LCO displays many improvements:\n(i) reduced charge-transfer and interfacial resistance; (ii) higher\ndischarge capacity (167.5 vs 155 mAh/g) at 0.2C; (iii) higher Coulombic\nefficiency (98.9 vs 97.8%) over 100 cycles; and (iv) higher rate capability\n(143 vs 80.1 mAh/g) at 4C. Structural and morphological characterizations\nhave substantiated the improved electrochemical behavior of bare and\nLi⁺-ACEI LCO cathodes against the Li anode.