Investigating the Electrocatalysis of a Ti<sub>3</sub>C<sub>2</sub>/Carbon Hybrid in Polysulfide Conversion of Lithium–Sulfur Batteries
Hangyu Zhou, Zhuyin Sui, Kamran Amin, Liangwen Lin, Haiyan Wang, Bao‐Hang Han
Abstract
Despite the fact that lithium–sulfur batteries are regarded as promising next-generation rechargeable battery systems owning to high theoretical specific capacity (1675 mA h g–1) and energy density (2600 W h kg–1), several issues such as poor electrical conductivity, sluggish redox kinetics, and severe “shuttle effect” in electrodes still hinder their practical application. MXenes, novel two-dimensional materials with high conductivity, regulable interlayer spacing, and abundant functional groups, are widely applied in energy storage and conversion fields. In this work, a Ti3C2/carbon hybrid with expanded interlayer spacing is synthesized by one-step heat treatment in molten potassium hydroxide. The subsequent experiments indicate that the as-prepared Ti3C2/carbon hybrid can effectively regulate polysulfide redox conversion and has strong chemisorption interaction to polysulfides. Consequently, the Ti3C2/carbon-based sulfur cathode boosts the performance in working lithium–sulfur batteries, in terms of an ultrahigh initial discharge capacity (1668 mA h g–1 at 0.1 C), an excellent rate performance (520 mA h g–1 at 5 C), and an outstanding capacity retention of 530 mA h g–1 after 500 cycles at 1 C with a low capacity fade rate of 0.05% per cycle and stable Coulombic efficiency (nearly 99%). The above results indicate that this composite with high catalytic activity is a potential host material for further high-performance lithium–sulfur batteries.