Surface engineering-induced highly dispersed and polycrystalline structured nickel phosphide nano catalysts for lithium-sulfur batteries

The shuttle effect and sluggish sulfur redox kinetics are the primary factors that influence the cycle life of lithium-sulfur (Li-S) batteries. Therefore, investigating electrocatalysts with a large number of active sites and high activity to improve the conversion kinetics of soluble lithium polysulfides (LiPS) is quite critical to solve these problems. In this study, surface engineering induced highly dispersible and polycrystalline structured catalyst of phosphatized nickel oxides (NiOPs) was prepared using bacterial cellulose (BNF) as a carrier and followed by partial phosphorization. Specifically, the as optimized nano NiOP-1 h (phosphating for 1 h) catalyst show an abundant polycrystalline structure of Ni₂P/Ni₅P₄ and also appropriate interaction with LiPS, which helps it greatly overperform the pristine NiO, N₂P and other partially phosphorized NiOP for enhancing the sulfur redox. The Li-S cells with paper-based NiOP-1 h electrodes can achieve a maximum capacity of 3.4 mAh cm⁻² at 0.15C, even with sulfur loading of 4 mg cm⁻² and lean electrolyte of 6.7 µL mg⁻¹. This method demonstrates the potential for preparing electrocatalysts characterized by high dispersibility and abundant active sites, offering applications in various other domains.