Realizing the high energy density and flexibility of a fabric electrode through hierarchical structure design.

Abstract

The exploration of high-energy density flexible electrodes through reasonable structural design is the key to realizing the overall portability and wearability of devices. Herein, a free-standing hybrid nanofabric with superior mechanical and electrochemical stabilities is reported for flexible lithium-ion batteries (LIBs). The hybrid nanofabric is prepared by electrospinning and carbonization, during which the self-cyclization of polyacrylonitrile (PAN) is hindered by its reaction with melamine, resulting in a highly disordered and expanded turbostratic carbon structure with nickel metal thiophosphate (NiPS3) nanosheets embedded in it. The coordinated movement of the electrospun-derived 1D nanofiber, the super toughness of the hard carbon structure and the interlayer slipping of NiPS3 endow the hybrid nanofabric with excellent tolerance to large-scale deformation. It can be folded three times in half and quickly return to its original state. When used as the anode for LIBs, no additional binder, conducting agent and current collector are needed. The free-standing anode not only shows excellent cycling (797.5 mA h g-1 after 1000 cycles at 1 A g-1) and rate (more than 56% capacity retained from 0.1 to 2 A g-1) performances, but also maintains its original electrochemical properties after being folded 300 times at 120°, 180° and 360°. This work provides a synergistic strategy to simultaneously enhance the energy density and flexibility of a fabric electrode, paving the way for the application of advanced flexible energy storage systems.