The immobilizing polysulfide mechanism of cadmium-doping carbon aerogels via a microtemplate for high performance Li–S batteries
Cadmium-doped carbon aerogels were successfully prepared via a microtemplate inducing strategy and subsequent high temperature carbonization. The controlled synthesis technology forms spherical carbon aerogels with uniform and interconnected porous structures. The as-prepared materials display large specific surface area and excellent conductivity. The loaded sulfur composites as cathode materials exhibit high discharge capacity and excellent cycling performance. Particularly, the designed P2-Cd-CA/S electrode with 78.9 wt% sulfur presents an initial discharge capacity of 1318 mA h g−1 at 0.2C. And it delivers an initial discharge capacity of 1189 mA h g−1 at 0.5C and still maintains 871 mA h g−1 after 300 cycles. The enhanced performance is mainly ascribed to the synergistic effect of the inductive graphitization of a microtemplate (3,4,9,10-perylenetetracarboxylic dianhydride) and the stronger anchoring for polysulfides of evenly distributed cadmium. Furthermore, the first-principles theoretical calculations further support the strong adsorption between CdO and polysulfides and affirmatively reveal the immobilizing mechanism.