Crystal transformation engineering for effective polysulfides blocking layer for excellent energy density lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) with ultra-high energy density are emerging as the best alternative for nextgeneration energy storage systems. Nevertheless, polysulfide (LiPS) shuttling induces rapid capacity diminution, and short battery lifespan, which seriously hinders their practical application. Herein, a solvothermal and controlled pyrolysis process was used to synthesize the metal-organic frameworks derived m-/c-ZrO2 heterojunction distributed on nitrogen-doped porous carbon (NC) and uniformly wrapped by graphene sheets. Electrochemical investigation demonstrates that the m-/c-ZrO2/NCG heterostructure modified separator can efficiently impede LiPSs shuttling and regulate the conversion reaction of long-chain LiPSs, which is further confirmed by first-principles theoretical calculations. The as-prepared m-/c-ZrO2/NCG-based LSBs showed remarkable cyclability with a decay rate of 0.023 % per cycle over 1000 cycles at a high rate of 2 C. Importantly, at very high sulfur loading of 6.8 mg cm-2, an excellent reversible specific capacity of 924.1 mAh g-1 at 0.2 C after 100 cycles is achieved, which is expected to obtain high energy performance. This work delivers a promised strategy for the rational design of multifunctional heterostructure for stable and safe LSBs, providing a means of narrowing the gap for the commercialization of high-energy next-generation electrochemical storage devices.

Automated summary

Researchers have synthesized a material with metal-organic frameworks derived m-/c-ZrO2 heterojunction distributed on nitrogen-doped porous carbon (NC) and uniformly wrapped by graphene sheets. This material can efficiently impede LiPSs shuttling and regulate the conversion reaction of long-chain LiPSs, leading to remarkable cyclability and high specific capacity in lithium-sulfur batteries. This study provides a promising strategy for the rational design of stable and safe lithium-sulfur batteries.