Cycling stability of lithium-ion batteries with pressure-treated NCM811 cathodes

Abstract

This study developed an effective approach for improving the cycling performance of NCM811-based lithium-ion batteries (LIBs) at a charge rate of 5C. The charge–discharge performance of LIBs with pressure-treated NCM811 cathodes was investigated. The cathode coating, comprising NCM811, acetylene black, and polyvinylidene fluoride, was compressed at pressures of 10–40 MPa. Galvanostatic charge–discharge tests revealed that a treatment pressure of 40 MPa improved the storage performance at ≥5C under the LIB full-cell configuration. After pressure treatment, NCM811-based LIBs exhibited excellent cycling stability over 500 charge–discharge cycles at 5C. After 500 cycles, energy-dispersive X-ray analysis confirmed that the dissolution of transition metals from the NCM811 cathode and their deposition at the graphite anode were inhibited. High-pressure treatment modified the morphology of the NCM811 cathodes, resulting in favorable electrochemical properties. The proposed NCM811 electrodes are promising for the development of power-type LIBs with high energy densities and long cycle lifetimes.