Conductor-Free Anode of Transition Metal Dichalcogenide Nanosheets Self-Assembled with Graft Polymer Li-Ion Channels

The development of anodes for lithium-ion batteries (LIBs) based on liquid-phase-exfoliated 2D transition metal dichalcogenide (TMD) nanosheets has been studied extensively because their intrinsic capacity is higher than graphite. Since most semiconducting TMDs possess low electrical conductivity and lithium-ion diffusivity, expensive processes are necessary such as the addition of conductive fillers, chemically converted metallic phase transformation, and topological nano-fabrication. Here, a novel conductor-free TMD nanosheet anode with graft-polymer ionic channels that ensures high stability and rate capability of the LIB is presented. The fluorinated polymer binder grafted with ionomers allows not only the efficient exfoliation of TMD nanosheets in the liquid phase to guarantee stable sheet-to-sheet separation but also provides self-assembled ionic channels through which lithium ions in the electrolyte readily arrive close to the surface of the nanosheets. Efficient electrochemical reduction of lithium ions occurs on the surface of the binary anode of MoS2 nanosheets, self-assembled with graft polymer ionic channels, resulting in a high-performance LIB with stability (90% retention rate after 1,000 cycles), rate capability (50% at 5 A g(-1)), and high cell capacity (933.1 mAh g(-1) at 0.1 A g(-1)). These TMD anodes that do not require additional processes, and offer a novel strategy for developing high performance large-scale TMD-based LIBs.

Automated summary

This study presents a conductor-free TMD nanosheet anode with a novel design of ionic channels, ensuring high stability and rate capability. The self-assembly of graft polymer ionic channels allows efficient electrochemical reduction of lithium ions on the nanosheet surface.