Lithium Intercalation Chemistry in TaS₂ Nanosheets for Lithium-Ion Batteries Anodes

Exploring novel two-dimensional layered transitional metal dichalcogenides and elucidating their reaction mechanism are critical to designing promising anode materials for lithium-ion batteries (LIBs). Herein, a novel layered TaS₂ nanosheet was obtained via a typical solid-phase reaction method followed by a simple ball-milling treatment, and first explored experimentally as an anode for LIBs. The TaS₂ nanosheet anode delivered an excellent cycling stability, with 234.6 mAh g^-1 after 500 cycles at 1 A g^-1. The optimized performance could be attributed to the large interlayer spacing, high conductivity, and reduced size of the TaS₂ nanosheet, which effectively alleviated the volume change during the reaction process and accelerated the Li⁺ or e^- transport. Especially, the TaS₂ nanosheet anode presented an unusual intercalation reaction mechanism, accompanied with a reversible phase transition from the 2H to the 1T phase during the first de-lithiation process, which is evidenced by the multiple ex situ characterizations, further revealing the enhanced electrochemical performance results from the 1T phase with the larger interlayer spacing and higher electrical conductivity. This work provides a novel insight into the intercalation reaction mechanism of TaS₂, which shows potential in high-performance LIBs.