Lithium Borate GlassCeramics and Multiwalled CarbonNanotube Composites as Efficient Sulfur Hosts for Enhanced Lithium–SulfurBatteries

Abstract

Lithium–sulfur (Li–S) batteries are one of the encouraging alternatives to conventional lithium-ion batteries. However, the dissolution of polysulfide and the low conductivity of the cathode materials are limitations. In this work, lithium borate (LBO) glass ceramics combined with a multiwalled carbon nanotube (CNT) and elemental sulfur, denoted LBO–CNT/S, were synthesized using simple techniques. This outstanding performance can be attributed to the synergistic interaction of LBO and CNT, which enhanced its unique properties. As a result, LBO–CNT/S delivered the highest electrochemical performance as a cathode in 30 cycles at 0.04 C. Additionally, the sulfur loading was evaluated for LBO–CNT/S, revealing a reversible capacity of about 700 mA h/g at 0.75 mg/cm², even at 0.2 C. After 100 cycles, the capacity retention dramatically dropped, remaining at 70.8%. Meanwhile, at a mass loading of 0.42 mg/cm², the capacity retention remained at 90.7%, reducing with negligible capacity fading. Therefore, strategies have been developed to improve the stability of Li–S batteries with low sulfur content, and glass-ceramic materials can be applied for electrode design in energy storage applications.