Two-dimensional self-assembled TiSe2 micro–nanoparticles toward high-performance sodium ion storage†

Abstract

Sodium-ion batteries (SIBs) are potential commercial energy storage devices. However, the inadequate long-term cycling stability and rate capability of anode materials have hindered the commercial applications of SIBs. TiSe₂ is regarded as a potential anode for SIBs owing to its high electrical conductivity and unique layered structure. Herein, a novel TiSe₂ anode for sodium storage at extraordinary current has been prepared through a simple one-step solid-phase selenization method. The layered micro–nanoparticles can not only ensure rapid ion/electron transport, but also effectively suppress structural collapse over repeated cycles. Benefiting from the design advantages, the layered TiSe₂ exhibits good structural stability, high pseudocapacitive behavior, and low impedance, thereby retaining a capacity of 76.7 mA h g⁻¹ at an ultra-high current density of 40 A g⁻¹ and a capacity of 155.6 mA h g⁻¹ even after 3000 cycles at 10 A g⁻¹. Moreover, in situ and ex situ technologies clearly reveal the reversible reaction mechanism, also ensuring favourable electrochemical performance.