Binder-free organic cathode based on nitroxide radical polymer-functionalized carbon nanotubes and gel polymer electrolyte for high-performance sodium organic polymer batteries

Abstract

The organic polymer battery is a promising alternative to the lithium ion battery, however its various properties need to be improved. In this study, we demonstrate an advanced organic radical battery (ORB) using a cathode based on poly(2,2,6,6-tetramethylpiperidine-4-yl-1-oxyl vinyl ether) (PTVE) and a microporous gel polymer electrolyte based on electrospun polyimide membrane. To improve upon the low electrical conductivity of PTVE, it is functionalized on carbon nanotubes (CNTs) by a dissolution-diffusion process. The PTVE-functionalized CNTs have a π–π* interaction between the two components, and could be formed into a dense electrode with reasonable porosity. The gel polymer electrolyte with the desired microporosity is also highly compatible. As a result, Na-ion organic full cells using PTVE-CNT composite electrode, gel polymer electrolyte, and hard carbon anode show good rate capability and stable cycling. The battery achieves discharging capacities of 128.6 and 68.2 mAh g-1 at 0.5 C and 10 C with 100% Coulombic efficiency and no self-discharge. Hence, this combination of composite electrode and gel polymer electrolyte lead to a safe, lightweight, environmentally benign, and sodium battery with high power-rate capability for various applications.