Status and prospects of electrocatalysts for lithium-sulfur battery under lean electrolyte and high sulfur loading conditions

Abstract

The high theoretical energy density (2600 Wh kg−1) and high theoretical specific capacity (1675 mAh/g) have led to the emergence of lithium-sulfur battery (LSB), which makes it one of the most potential energy storage systems to achieve commercialization in place of lithium-ion battery. Unfortunately, the slow kinetics and the shuttle effect of polysulfides in LSB severely hamper its rate performances and operating life. The cycling performances and sulfur utilization of LSB have been improved by most sulfur host materials as electrocatalysts under excess electrolyte. However, considering the practical application of LSB, lean electrolyte and high sulfur loading conditions are necessary. In this review, research progress of electrocatalysts in LSB under lean electrolyte and high sulfur loading conditions are introduced. Electrocatalysts are mainly divided into nonmetallic catalysts and metal-based catalysts. Nonmetallic catalysts include nonmetallic compounds, graphene, carbon nanotubes and heteroatom-doped carbon materials. Metal-based catalysts are composed of cobalt-based catalysts, molybdenum-based catalysts, iron-based catalysts and multi-metal-based heterostructures. The improvement battery performances and the related catalytic mechanism of electrocatalysts are comprehensively discussed. Finally, the challenges and prospects on exploring further to achieve commercial applications of LSB are presented.