A 3D multifunctional architecture for lithium–sulfur batteries with high areal capacity

Abstract

Lithium–sulfur (Li–S) batteries are highly attractive as next-generation electrochemical energy-storage technologies because they can provide a high energy density at a low cost. However, the performance degradation of sulfur cathodes with high mass loadings remains a significant challenge to be addressed. Here, a 3D multifunctional integrated and sponge-like architecture is designed as the cathode framework, which provides a favorable balance between high sulfur loadings and uncompromised electrochemical performances. In this architecture, a highly porous nitrogen-doped carbon fiber foam is used as a 3D current collector and host for sulfur accommodation and a thin graphene layer is used for polysulfide interception, which not only facilitates fast electron and lithium-ion transport but also enables effective active material immobilization by both physical restriction and chemical adsorption. With a sulfur loading of 7.7 mg cm⁻², high areal capacities up to 8.7 mAh cm⁻² are attained together with excellent cycling stability over 500 cycles. This approach demonstrates a new concept for the construction of cathode architectures for practical Li–S batteries and can be extended to other battery systems.