Crystal-structure-matched FePO4 Surface-coating on LiCoPO4/MWCNT Nanocomposites for Long Lifecycle 5V Class Lithium Ion Batteries

Abstract

Stable high-voltage operation of LiCoPO4 (LCP) was successfully achieved via crystal-structure-matched surface coating using FePO4 (FP) with an identical olivine structure to the LCP. The efficient formation of Fe3+-rich surface together with the partial dissolution of Fe3+ into LCP matrix yielded the excellent cycle performance with 99% of capacity retention at 100th cycle, with a minimized Fe3+ dosage compared to the methods previously reported. This work confirms that the existence of the Fe3+ on the LCP surface is an important factor to bring about the stability of electrode/electrolyte interface.