Suppressing the Voltage Decay and Enhancing the Electrochemical Performance of Li1.2Mn0.54Co0.13Ni0.13O2 by Multifunctional Nb2O5 Coating

Abstract

This study focuses on suppressing the voltage decay and improving the electrochemical performance of Li-rich and manganese-based (LRM) material by Nb2O5 coating, which is realized by an effective soft-chemical route using a mixture of ethanol and water as co-solvent. After Nb2O5 coating, the resulted material demonstrates superior electrochemical performance as cathode material for LIBs. Particularly, it shows an excellent capacity retention of 98 % after 200 cycles at 1 C (1 C=250 mA g−1). Voltage decay within cycling is also obviously suppressed by Nb2O5 coating. Moreover, it exhibits superior rate capacities, delivering 189 and 152 mAh g−1 at high current densities of 2 and 5 C, respectively. The improved electrochemical performance of Nb2O5 coated sample can be attributed to that Nb2O5 can suppress the phase transformation and voltage decay by acting as not only a fast ion conductor to accelerate the lithium ion diffusion at the cathode/electrolyte interface, but also an inert protective layer to reduce the direct contact between the cathode and electrolyte.