Doping and Surface Modification Enhance the Applicability of Nanostructured Fullerene-MWCNT Hybrid Draped LiNi_(0.1)Mg_(0.1)Co_(0.8)O_2 as High Efficient Cathode Material for Lithium-Ion Batteries

摘要

Development of high performance cathode materials, layer-structured ternary LiNixCoyM1-x-yO2 cathode materials have attracted much attention owing to their larger capacity and higher energy density. Persistent efforts have been devoted to tackling certain issues like low electronic conductivity and poor structural stability. Dual strategy of Mg doping and surface modification of the cathode material was adopted to improve the performance of the battery. Fullerene-Multi-Walled Carbon Nanotube (MWCNT) hybrid draped LiNi0.1Mg0.1Co0.8O2 nanocomposite was synthesized by a simple chemical route. The fullerene-MWCNT hybrid modifies the surface of pristine LiNi0.1Mg0.1Co0.8O2 thereby improves the electrochemical performance and maintains the structural stability of the cathode material. Pristine LiNi0.1Mg0.1Co0.8O2 and LiNi0.1Mg0.1Co0.8O2/fullerene-MWCNT nanocomposite were studied using various advanced characterization techniques such as X-ray diffraction (XRD), Micro-Raman spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), X-ray Photoelectron Spectroscopy (XPS), and High-Resolution Transmission Electron Microscopy (HRTEM). It is found that LiNi0.1Mg0.1Co0.8O2 particles retain their structural integrity after being enveloped with a fullerene-MWCNT hybrid. The electrochemical performance was investigated with cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) test and electrochemical impedance spectroscopy (EIS). As prepared LiNi0.1Mg0.1Co0.8O2, when deployed in the form of LiNi0.1Mg0.1Co0.8O2/fullerene-MWCNT composite exhibits a high specific capacity of 208 mAh g(-1). Fullerene-MWCNT hybrid draped LiNi0.1Mg0.1Co0.8O2 nanocomposite provides an effective Li+ and electron channel that significantly increased the Li-ion diffusion coefficient and reduced the charge transfer resistance. Besides,the lithium diffusion coefficient increased from 5.13 x 10(-13) (Li/LiNi0.1Mg0.1Co0.8O2) to 8.313 x 10(-13) cm(2) s(-1) due to the improved kinetics of Li insertion/extraction process in Li/LiNi0.1Mg0.1Co0.8O2 + fullerene-MWCNT cell.