Nitrogen-Doped Graphene-Supported Straw-Like CoSe<sub>2</sub> for Rapid and Stable Sodium-Ion Storage.

Xu, Chong; Chen, Kaiyi; Ma, Guang; Wang, Ye; Wu, Siwei; Che, Sai; Cui, Yongpeng; Yang, Wang et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

Cobalt diselenide (CoSe<sub>2</sub>) materials exhibit significant potential in sodium-ion batteries (SIBs) owing to their high theoretical specific capacity and excellent cycling stability. However, the conductivity and volume expansion of CoSe<sub>2</sub> limit its rate performance and cycling stability. Herein, a nitrogen-doped reduced graphene oxide (N-rGO) supported straw-like CoSe<sub>2</sub> anode material (CoSe<sub>2</sub>/N-rGO) is synthesized via a hydrothermal method. Experimental results show that nitrogen doping improves the conductivity and structural stability of CoSe<sub>2</sub>/N-rGO, enabling excellent rate performance (311.75 mAh g<sup>-1</sup> at 10 A g<sup>-1</sup>) and high cycling stability (356.78 mAh g<sup>-1</sup> after 1000 cycles at 1 A g<sup>-1</sup>). Notably, the CoSe<sub>2</sub>/N-rGO||NVP full cell exhibits a capacity of 117.4 mAh g<sup>-1</sup> at 0.1 C, approaching 98.7% of the calculated maximum for NVP (118 mAh g<sup>-1</sup>). This approach offers new insights and valuable guidance for the structure of efficient electrode materials for energy storage systems.