Synthesis of CoP@B,N,P co-doped porous carbon by a supramolecular gel self-assembly method for lithium–sulfur battery separator modification

Abstract

Lithium–sulfur batteries (LSBs) are regarded as promising next-generation batteries due to their high abundance and high theoretical energy density. However, the commercial application of LSBs is hindered by the shuttle effect of soluble lithium polysulfides (LiPSs). Hence, we synthesised B, N, P co-doped three-dimensional hierarchical porous carbon materials, uniformly dispersed with CoP nanoparticles, and utilized them as the coating material for the PE separator. The catalytic and adsorption capacity of the composite material was significantly enhanced by CoP. Both experimental and theoretical calculations show that the LiPS adsorption capacity of the composite material is significantly enhanced after the introduction of B atoms. As a result, the assembled LSBs with the CoP@BNPC/PE separator show excellent long-term stability (940.8 mA h g⁻¹ after 500 cycles at 1.0 C, and only a 0.026% decay rate per cycle) and superior rate performance (613.6 mA h g⁻¹ at 5.0 C). Our work further proves that a modified separator is an effective strategy to promote the commercialization of LSBs.