Electroactive-catalytic conductive framework for aluminum-sulfur batteries

Rechargeable aluminum‒sulfur batteries (RASBs), despite the great advantage of high energy density and low cost, are suffering from insulative solid sulfur species and sluggish reaction kinetics. The routine solution of introducing an excessive amount of inactive carbon will cause the low active material's proportion and thus high electrode porosity, dramatically compromising the energy densities. More importantly, the high Gibbs free energy of the Al2S3 decomposition remains unsolved. Herein, an Al3+-intercalative and catalytic electronic conductive framework (ECF) is constructed by Mo6S8 to replace conventional inactive carbon, in which Mo6S8 will build an efficient conductive network, provide high Al-ion storage capability, have a strong affinity to polysulfides to restrain their dissolution, and show superior catalytic activity on the decomposition of Al2S3. Consequently, the Mo6S8/S cathode achieves a highly competitive specific energy of 371 Wh/kgcathode (ca), with the voltage hysteresis of sulfur redox markedly decreased by 569 mV. Our Al3+-intercalative and catalytic ECF notably enhances the specific energy and energy efficiency of RASBs, which will push multivalent metal-sulfur batteries forward to practical application.