Hierarchical Fe2O3@CNF fabric decorated with MoS2 nanosheets as a robust anode for flexible lithium-ion batteries exhibiting ultrahigh areal capacity

Abstract

Flexible lithium ion batteries (LIBs) have been recognized as indispensable energy storage devices compatible with the emerging flexible/stretchable wearable electronics. Herein, we design a three-dimensional (3D) hierarchical Fe₂O₃@CNFs@MoS₂ fabric film as a self-standing and robust anode, in which ultrathin curly MoS₂ nanosheets are tightly anchored onto the surface of an interconnected Fe₂O₃@carbon nanofiber (CNF) substrate. The flexible Fe₂O₃@CNFs fabric electrode can establish a 3D continuous conducting network and maintain superior structural integrity, while the unique hierarchical MoS₂ nanosheets can further shorten the Li⁺ diffusion path, expand the interfacial contact and offer increased active sites for reversible lithium insertion/extraction reactions. The as-prepared hierarchical Fe₂O₃@CNFs@MoS₂ fabric is directly used as a film anode for LIB half-cells, which exhibits an excellent reversible capacity of 938 mA h g⁻¹ at 0.2 A g⁻¹ after 300 cycles and high rate capabilities of 304 mA h g⁻¹ at 5.0 A g⁻¹. When combined with a LiCoO₂ (LCO) cathode and PVDF/PPC gel polymer electrolyte, the Fe₂O₃@CNFs@MoS₂ fabric-based quasi-solid-state flexible full cell realizes outstanding capacity performance and mechanical flexibility. It delivers an ultrahigh areal specific capacity of ≈6.47 mA h cm⁻², superior cycling tolerance and a high capacity retention of 90.8% after 300 cycles even in the 90° bending position, which are among those of the so far reported best-performing flexible LIBs. Along with a simple and eco-friendly fabrication process, this 3D nanoarchitectured Fe₂O₃@CNFs@MoS₂ fabric could provide a promising avenue toward high performance flexible LIBs and other rechargeable batteries.