Superior Electrochemical Properties of Ni-Rich LiNi0.85Co0.05Mn0.10O2 Cathode with the Stable Polypyrrole Coating and Boron Doping for Li-Ion Batteries

Abstract

Ni-rich cathode materials have attracted much attention due to the high energy density and low cost. However, the poor cycling performance and low rate capacity have produced a serious impact on the practical commercial application. In this work, the B3+ incorporation and polypyrrole coating were both applied to enhance the electrochemical properties of LiNi0.85Co0.05Mn0.10O2 by using the co-precipitation process followed by a chemical vapor phase polymerization way. Herein, the B3+ incorporation into crystal structure could enlarge the lattice spacing, contributing to accelerating the Li+ insertion/extraction speed and enhancing the structural stability during cycling. The polypyrrole surface coating played a great effect on preventing cathode surface from the electrolyte erosion owing to a shield of polypyrrole. As a result, a maximum discharge capacity of 129.8 mAh g−1 at 5 C high rate and prominently enhanced cycling performance with capacity retention of 90.1% after 300 cycles were acquired for the Polypyrrole coated LiNi0.835Co0.05Mn0.10B0.015O2. By comparison, the pristine LNCMO cathode demonstrated a fast decaying capacity and delivered a capacity retention of only 81.9%.