Acid-corrosion-formed amorphous phosphate surfaces improve electrochemical stability of LiNi0.80Co0.15Al0.05O2 cathodes

Abstract We report a surface modification of LiNi0.8Co0.15Al0.05O2 (NCA) materials with a phosphate layer via a room-temperature corrosion approach from H3PO4-ethanol solution. The phosphate layer is of amorphous nature with a thickness of 2∼3 nm, and consequently, NCA maintains its bulk structure during cycling and possesses significantly enhanced rate property of 153.7 mA h g−1 at 5C. Simultaneously, such a modified system demonstrates an excellent cycling stability (107.5 mA h g−1) and coulombic efficiency (>90 %) after 300 cycles at 5C. The findings highlight that the acid corrosion treatment represents a facile and efficient way in developing advanced NCA cathodes.