V2C/VO2 nanoribbon intertwined nanosheet dual heterostructure for highly flexible and robust lithium–sulfur batteries

Abstract

The construction of self-supporting and robust electrodes with high energy density and enduring redox chemistry is pivotal for developing high-performance lithium–sulfur (Li–S) batteries towards flexible electronics, whose practical applications are hampered by the shuttling of lithium polysulfide (LiPS) and sluggish reaction kinetics. 2D heterostructured materials integrating laminated morphology and stable compositions have attracted intensive interest for rapid ion/electron transfer, which are desperately needed in various energy storage applications. Herein, MXene-based flexible sulfur cathodes utilizing V₂C/VO₂ nanoribbon intertwined V₂C/VO₂ nanosheet (VCOR–VCOS) dual heterostructures as skeleton matrices are designed, in which the V₂C/VO₂ nanoribbon is in situ pillared between the adjacent V₂C/VO₂ layers during the hydrothermal process, providing a lightweight sandwich-type architecture with high mechanical robustness, unobstructed electron/Li⁺ ion transfer and catalytic properties for LiPS redox reactions. By virtue of these preponderances of VCOR–VCOS, pouch cells with an areal S loading of 6.0 mg cm⁻² and an electrolyte to sulfur ratio of 4.5 μL mg⁻¹ deliver a superior areal capacity of 6.3 mA h cm⁻² and excellent capacity retention under arbitrary bending conditions, which provide a ponderable reference for future flexible electronic devices.