Robust P-Se bond coupling of atomically amorphous W-P clusters to crystalline WSe2 via dual p-band centers for enhanced sodium-ion storage

Disordered design in electrodes is of great interest in the field of energy storage and conversion. Amorphization and bond coupling of components in heterojunctions can further improve the energy storage properties of electrodes and extend their reaction mechanisms. Herein, deep modulation of storage sites is achieved by constructing a composite (W-P/WSe2/C) based on atomically amorphous W-P clusters (W-P2 coordination) and crystalline WSe2 in carbon nanosheets. The W-P clusters are enriched with unsaturated vacancy defects and bulk-phase undifferentiated storage sites, while theWSe2 nanosheets frequently undergo structural collapse and agglomeration. Hybridization of suspended P sites with Se in p-p orbitals creates dual p-band centers and robust P-Se bond coupling, which can effectively enhance the sustainability of W-P/WSe2 heterojunction and the storage properties of WSe2. By exciting free electrons and optimizing charge density, the bond coupling remarkably improves the adsorption and migration of Na+ as well as the electrochemical reactivity of the electrode. As an anode for sodium-ion batteries (SIBs), W-P/WSe2/C evinces exceptional storage properties and high competitiveness (217.4 mAh g − 1 reversible capacity after 5000 cycles at 10.0 A g − 1). These findings illustrate that amorphous clusters can greatly improve the energy storage properties of selenides, which is valuable for the development of high-performance SIBs.