Selective adsorption-involved formation of NMC532/PANI microparticles with high ageing resistance and improved electrochemical performance

Abstract

Abstract Surface modification offers an alternative strategy to improve both ageing resistance and electrochemical performance of cathode materials for lithium-ion batteries. From the viewpoint of real application, surface modification of the cathode materials should be designed with scientificity, effectiveness, low cost, less Li+ leaching, and remained tap density. In this contribution, a selective adsorption-involved in-situ growth of polyaniline (PANI) nanoparticles on LiNi0.5Mn0.3Co0.2O2 (NMC532) has been designed through a room-temperature-and-pressure chemical vapor deposition technique. The selective growth of PANI on NMC532 is based on theoretical computation results that multivalent Ni, Mn, and Co are capable of specifically conjugating and activating aniline molecules and, hence, initiating in-situ oxidation polymerization. With only trace amount of aniline monomer, the resulting PANI nanoparticles-inlaid NMC532 microparticles can endure four-month ageing in ambient atmosphere and exhibit improved electrochemical performance at both room temperature and 55 °C, compared with pristine NMC532. The improved electrochemical performance of NMC532/PANI is attributed to the enhanced structural stability of NMC532 and inhibited side reactions related to Li2CO3 formation, PVDF degradation, electrolyte decomposition, and transition-metal dissolution, owing to PANI modification.