Fabrication of CNTs/MnO2 composite as a wrapping layer for surface modification of Cr-doped LiNi0.5Mn1.5O4 for lithium ion batteries

Abstract

Needle-like MnO₂ is deposited on the surface of CNTs using a simple redox reaction and simultaneously forms a special wrapping layer on the surface and among the particles of Cr-doped LiNi_0.5Mn_1.5O₄ through an auto-grow process. The CNTs act as a conductive network of electrons and the needle-like MnO₂ increases the contact points among the particles and furthermore provides additional Li⁺ diffusion paths. The CNTs/MnO₂ composite is also a protective layer to suppress the side reaction between the electrode and the electrolyte. The CNTs/MnO₂-coated, Cr-doped LiNi_0.5Mn_1.5O₄ (CNTs/MnO₂–Cr-LNMO) shows superior electrochemical properties, with a high specific capacity and excellent cycling stability at high voltage and high rate.