Highly Catalytic CoP@N, P-Codoped Porous Carbon Synthesized by a Supramolecular Gel and Salt Template Method for Li–S Batteries

Abstract

Lithium polysulfides (LiPSs) shuttling effect is the main problem to be solved for cathode materials of lithium–sulfur batteries. The adsorption and catalytic conversion of LiPSs by host materials have become the main focus of cathode materials. In this work, transition metal phosphides are combined with three-dimensional carbon nanosheets to form an efficient and stable sulfur host material. The designed composite material is effective in solving the problems of slow reaction kinetics of Li–S batteries and LiPSs shuttling. Here, through the supramolecular self-assembly process of melamine and phytic acid, combined with soluble salt template technology, N- and P-codoped three-dimensional hierarchical porous carbon materials with uniformly dispersed CoP nanoparticles were efficiently synthesized. The catalytic effect of CoP nanoparticles improves the reaction kinetics effectively of LiPS conversion. The strong polarity of CoP nanoparticles is beneficial to the adsorption of polysulfide ions. Moreover, the high specific area provides more LiPS adsorption sites, and the doping of N and P heteroatoms further increases the active sites of the composites. The experimental results and theoretical calculations show that the introduction of CoP promotes the conversion of LiPSs and accelerates the nucleation rate of Li2S, thereby improving the electrochemical performance of the composite as a sulfur host for lithium–sulfur batteries.

A dual-functional matrix with high absorption and electrocatalysis to suppress the shuttle effect in lithium–selenium batteries

“…4g–i, a plot was generated between the scanning rate and the square root of the peak current, revealing a clear linear relationship. Therefore, the Li + diffusion efficiency was calculated using the Randles–Sevcik formula 42–44 where I p represents the peak current, n represents the number of electron transfers in the redox reaction, A represents the electrode area, C Li + reflects the Li + concentration, and v represents the sweep rate. The values of I p for all cathodic and anodic peaks (1, 2, and 3) showed a linear increase with v 0.5 .…”

A review of metal phosphides with catalytic effects in Li–S batteries: boosting the redox kinetics

“…80,81 Meanwhile, Yin and co-workers designed CoP@N and P-codoped porous carbon (CoP@N, P@C) as host materials for Li–S batteries. 82 The adsorption of polysulfides is facilitated by CoP, and its catalytic effect effectively enhances the reaction kinetics between polysulfides. Furthermore, the doping of N and P further increases the active sites of the composite material.…”

“…In comparison to other polar metal compounds, phosphides have the following features: (i) exhibiting metallic properties and even demonstrating superconductivity; (ii) offering high catalytic sites for the conversion of LPSs; (iii) being procured by a simple and gentle synthesis procedure. [44][45][46] In this article, we offer a comprehensive overview of the development of cathode hosts for Li-S batteries and systematically analyze the adsorption capabilities and catalytic effects of metal phosphides on electrochemical reactions in Li-S batteries. A summary of transition metal phosphides for Li-S battery applications is depicted in Fig.…”