CuSe2 Nanocubes Enabling Efficient Sodium Storage

As the most promising candidate for lithium-ion batteries (LIBs), the electrochemical performance of sodium-ion batteries (SIBs) is highly dependent on the electrode materials. Copper selenides have established themselves as potential anode materials for SIBs due to their high theoretical capacity and good conductivity. However, the poor rate performance and fast capacity fading are the major challenges to their practical application in SIBs. Herein, single-crystalline CuSe2 nanocubes (CuSe2 NCs) are successfully synthesized via a solvothermal method. As an anode of SIBs, the CuSe2 NCs render an almost 100% initial Coulombic efficiency, an outstanding long cycle life, e.g., 380 mA h g-1 after 1700 cycles at 10 A g-1, and an unprecedented rate performance of 344 mA h g-1 at 50 A g-1. Ex situ X-ray diffraction (XRD) patterns reveal the crystalline transformation of energy-storage materials, and the density functional theory (DFT) conclusion suggests that fast and stable ion diffusion kinetics enhances their electrochemical performance upon sodiation/desodiaton. The investigation into the mechanism provides a theoretical basis for subsequent practical applications.

Automated summary

As a potential anode material for sodium-ion batteries, CuSe2 nanocubes exhibit excellent electrochemical performance with high initial Coulombic efficiency, long cycle life, and unprecedented rate performance. The investigation into crystalline transformation and ion diffusion kinetics provides a theoretical basis for practical applications.