Designing and tuning the components of random terpolymers toward Ampere-hour-scale organic lithium batteries

Abstract

Organic electrode materials have been developed for decades because of their tunable structures, environmental compatibility and low carbon footprint. Limited by the contradiction between the functions of organic groups and the low specific capacity of organic cathodes, organic lithium batteries hardly simultaneously achieve high specific capacity, stable cycling and high rate performance in Ampere-hour-scale pouch cells. Herein, we developed a general strategy to construct a series of random terpolymer cathode materials by tuning their components related to electrochemical performance. In terpolymers, sulfur chains, propyl groups and benzoquinone/pyridine groups are chosen as active components, carbon backbones and functional groups, respectively. Benzoquinone/pyridine groups with a low content in terpolymers not only promote ionic conductivity and reaction kinetics, but also ensure a high sulfur content. An Ampere-hour-scale pouch cell retains 85% capacity after 80 cycles, and the energy density of the cathode materials is over 870 W h kg⁻¹. The strategy provides new insight into the construction of organic lithium batteries with a high energy density promising for practical applications.