Self-Assembled Bipolar Metals with Hollow Carbon Spheres for High-Performance Li–S Battery Cathodes

Abstract

The shuttling effect and sluggish redox kinetics of polysulfides are the main obstacles that restrict the practical application of lithium–sulfur (Li–S) batteries. Herein, in this work, cathode material embedded with bipolar metals Ti and Co prepared by a facile self-assembly process using hollow carbon nanospheres (HCSs), MXene nanosheets, and CoO(OH) has been reported. Due to the strong chemical adsorption and high catalytic activity introduced by the bipolar metal related active sites, the Li–S battery with the HCS@Co–MXene/S cathode shows the lowest charge transfer resistance and the best rate capability compared with HCS/S and HCS@MXene/S cathodes. Moreover, the battery delivers a high initial discharge capacity of 1309 mA h g–1, which maintains at 570 mA h g–1 after 300 cycles at 0.5 C. Even at an elevated discharge current of 1 C, the battery retains a reversible capacity of 728 mA h g–1 over 120 cycles. Therefore, with the embedding of bipolar metals, the current Li–S battery cathode demonstrates superior cycling stability than the reference cathodes. The findings in this work exhibit a promising prospect for facile assembling of the high-performance Li–S battery cathode and the resultant device.