Degradable Radical Polymer Cathode for Lithium Battery with Long-Term Cycling Capability

Abstract

Polymer-based organic electrodes for rechargeable batteries are attractive due to their design flexibility, sustainability, and environmental compatibility. Unfortunately, waste management of conventional polymer materials typically involves incineration, which emits greenhouse gases. Consequently, degradable polymers should be ideal candidates for future green batteries. However, to date, degradable polymer electrodes have been rarely reported. The few that have been developed exhibit very low capacities (<40 mAh g^-1) and poor cycle stability (<100 cycles). Herein, we synthesize a degradable polymer cathode for lithium batteries by copolymerizing 2,3-dihydrofuran with TEMPO-containing norbornene derivatives. This polymer cathode demonstrates a two-electron redox reaction charge storage mechanism, exhibiting a high reversible capacity of 100.4 mAh g^-1 and a long cycle life of over 1000 cycles. Furthermore, under a mild acidic environment, this polymer electrode material undergoes complete decomposition via the hydrolysis of enol ethers, confirmed by gel permeation chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. These encouraging results shed light on the design of degradable polymer electrodes.

Keywords: Organic electrode materials; Organic radical cathode; Polymer degradation; Polymer-based batteries.