Low-Cost Organodisulfide Polymer for Ultrafast High-Capacity Cathode Materials

Traditional inorganic cathode materials are currentlyfacing serioustechnical bottlenecks due to the use of transition metals with limitedresources (such as Co and Ni) and a relatively low specific capacity(<300 mAh g(-1)). Organic cathode materials haveno resource problem and a large theoretical specific capacity (upto 1000 mAh g(-1)), simply because they only containextremely rich and light elements, such as C, N, O, S, and H. Meanwhile,they have broad design and development space, owing to the varietyof functional groups with lithiation activity. However, organic cathodematerials also have issues in terms of practical applications, suchas the dissolution and loss of active substances and low conductivity.For most of the polymers that aim to solve these problems, the rawmaterials are expensive, and the synthesis process is complicated.Moreover, their theoretical specific capacity is usually below 200mAh g(-1). Herein, we report a low-cost organic disulfidepolymer with a theoretical specific capacity of 462 mAh g(-1). After incorporation with graphene, this polymer has excellent highrate performance in ether electrolytes. It has an energy density of1070 Wh kg(-1) at a power density of 185 W kg(-1). Even at a power density of 33,280 W kg(-1) (40 C), the energy density still remains at 200 Wh kg(-1), while the specific capacity is retained at 57% after 10,000 cyclesat 40 C.