Nanoporous Cobalt–Nitrogen–Carbon Catalyst-Based Multifunctional Interlayer for Enhanced Li–S Battery Performance

Abstract

The lithium−sulfur battery is considered to be a prospective candidate for the next-generation energy storage system. The practical application of the lithium−sulfur battery is impeded by several existing challenges, especially the lithium polysulfide (LiPS) "shuttle effect," which leads to low utilization of sulfur and poor cycle life. To alleviate the "shuttle effect", herein, we fabricate a nanoporous metal−nitrogen−carbon catalyst, that is, Co−N−C, combined with graphene (G) as a multifunctional separator coating layer. The Co−N−C/G interlayer exhibits several merits to improve the battery performance, including (1) nanoporous structure that facilitates ionic transport, (2) abundant Co active sites and polar nitrogen-rich carbon surface that can adsorb and immobilize LiPSs, (3) highly dispersed Co sites that are able to accelerate the sulfur redox reaction kinetics, and (4) excellent electrical conductivity for further sulphur utilization. The Co−N−C/G-coated separator endows the Li−S battery with excellent cyclic performance and rate capability. This study proposes a guidance to construct functional separators for enhanced lithium− sulfur battery performance.

Artificially Layered CoSe2 Nanosheets by a Dual-Templating Strategy for High-Performance Lithium–Sulfur Batteries

“…The electrochemical impedance spectroscopy (EIS) plots of the three symmetrical cells (Figure e) show that they have a similar series resistance ( R s ) of 5.6 Ω, revealing a small difference in conductivity of the electrodes. The semicircles represent the charge transfer resistance ( R ct ) at the electrode/electrolyte interface. , Compared with the CoSe 2 /CFC||CoSe 2 /CFC (25.1 Ω) and CFC||CFC (72.1 Ω) cells, the L-CoSe 2 /CFC||L-CoSe 2 /CFC cell delivers an obviously decreased R ct value of 3.5 Ω, thereby indicating that L-CoSe 2 /CFC realizes rapid charge transfer in the polysulfide conversion process. Therefore, both CV and EIS results demonstrate that L-CoSe 2 nanosheets have a better catalytic performance and accelerated redox reaction kinetics toward soluble LiPS conversion.…”

Promoting the application of sulfur electrodes in lithium sulfur batteries: a review about the optimization

“…Two important strategies are conducted to improve the stability of sulfur by regulation in host materials, one focuses on designing the interfacial interaction to improving the kinetics of sulfur-active materials, while the other pays attention to developing advanced structures to capture polysulfides. For example, introducing conductive three-dimensional(3D) structure into the sulfur electrode or modifying the chemical properties of the sulfur by advanced reactions were demonstrated effective to achieve high-performance sulfur electrodes [1], [2]. In lithium-sulfur batteries, the host material's porousness may restrict the movement and dissolution of lithium polysulfide.…”

Regulating Electrocatalytic Polysulfides Redox Kinetics through Manipulating Surface Electronic Structure of Molybdenum-Based Catalysts for High-Performance Lithium-Sulfur Batteries

“…Many electrocatalysts, including heteroatom-doped carbonaceous materials, − metal borides, − carbide, nitrides, − oxides, , fluoride, phosphides, − sulfides, , selenides, − alloys, , single-atom catalysts, ,− and heterostructure, − have been used in Li-S electrochemical systems. For example, Zou et al synthesized LaNiO 3 catalyst to immobilize the LiPSs and catalytically enhance the redox conversion, displaying an initial specific capacity of 1184 mAh g –1 at 0.1C and stable cyclic performance over 500 cycles .…”