Densely Packed Vertically Oriented WSe2 Nanosheets Synthesized by Chemical Vapor Deposition for Lithium-Ion Batteries.

Tungsten diselenide (WSe2) has emerged as a highly promising material for lithium/sodium-ion batteries due to its exceptional electrical and chemical properties and unique sandwich-like two-dimensional structures. In this work, we present a chemical vapor deposition approach for synthesizing densely packed vertically oriented 2H-phase WSe2 nanosheets uniformly grown on tungsten foil. As an electrode material, the as-synthesized WSe2 exhibits remarkable electrochemical performance including excellent cycling stability, high-rate capability, and superior electrochemical activity. The WSe2 nanosheets demonstrate a high reversible specific capacity of 159.3 mAh g-1 at a current density of 5 A g-1, maintaining a near-100% Coulombic efficiency over 2400 cycles. The underlying mechanism governing electrochemical performance was further investigated using first-principles density functional theory computations. These findings underscore the potential of WSe2 nanosheets as high-performance materials for next-generation LIBs.