Chemically Synthesised ϒ-MnO2, and β-MnO2/Single Wall Carbon Nanotube Composites As a Promising High Capacity Cathode Materials for Lithium-Ion Batteries

Abstract

This work reports the ϒ-MnO2, and β-MnO2 single wall carbon nanotube (SWCNT) nanocomposite cathode material synthesised successfully by chemical method for lithium-ion batteries. The electrochemical properties galvanostatic charge-discharge, cycle ability, rate performance and cyclic voltammetry were greatly enhanced by using the (SWCNT) composite cathode as a comparison to the pristine ϒ-MnO2, and β-MnO2. As a consequence, the modified (SWCNT) composite cathode material exhibits superior initial discharge capacity 255 mAh g-1 at 0.1C with coulombic efficiency of 99.22% and 118 mAh g-1 at 1C with a capacity retention (coulombic efficiency) of 95.5% (99.9%) after 100 cycles in the potential window of 2.0-4.5V (vs Li/Li+). In comparison pristine β-MnO2 exhibit only 169 mAh g-1 at 0.1C, corresponding to lower initial coulombic efficiency of 97% and 73 mAh g-1 at 1C with capacity retention (coulombic efficiency) of 71.4% (92%) after 100 cycles. The significant improvement in the de-/lithiation kinetic can be accredited to the enhancement in apparent lithium ion diffusion coefficient and electronic conductivity making it more applicable in high power commercialization.