Nickel–Nitrogen–Carbon Nanoparticles as Polysulfide Adjustment Layers for Lithium–Sulfur Batteries

Abstract

Lithium−sulfur (Li−S) batteries have become promising advanced energy storage and conversion devices because of their high theoretical energy density and specific capacity. Nevertheless, the shuttle effect and slow conversion kinetics of soluble lithium polysulfides (LPSs) have a effect on battery performance. Herein, a Zn−Ni−MOF precursor was synthesized and used to prepare nickel−nitrogen−carbon (Ni−N−C) nanomaterials by removing Zn particles via high-temperature annealing and sacrificial template methods. By incorporating these materials into the Li−S battery separator, the LPS can be effectively blocked and trapped, leading to a conspicuous mitigation of the shuttle effect. Simultaneously, the effective active sites distributed on the surface of Ni−N−C materials facilitate rapid LPSs conversion, resulting in a significant enhancement in electrochemical performance. At a current rate of 0.1C, the initial discharge-specific capacity of 1534 mAh g −1 can be obtained. When the charge−discharge rate is increased to 0.5C, the initial discharge-specific capacity can be measured as 1209 mAh g −1 with a capacity decay rate of only 0.06% per cycle after 300 cycles. Notably, under high-S loading conditions (4.5 mg cm −2 ), the initial specific capacity is 827.1 mAh g −1 and remains at 634.4 mAh g −1 after 162 cycles at 0.1C. These findings highlight the efficacy of utilizing MOF derivatives to modify conventional Li−S battery separators, effectively mitigating the shuttle effect and enhancing the electrochemical performance of Li−S batteries.