CoNiSe2 Nanoparticles Embedded in Pod‐Like N‐Doped Carbon Nanofibers for High‐Performance Sodium‐Ion Batteries

Sluggish kinetics and severe volume expansion critically limit the electrochemical performance of sodium‐ion batteries (SIBs). Herein, a novel material combining CoNiSe 2 nanoparticles with pod‐like N‐doped carbon nanofibers (CoNiSe 2 /PCNFs) is designed and fabricated. The bimetallic selenide of CoNiSe 2 combines the redox characteristics of Co and Ni, which offers more redox active sites for Na + adsorption. The nanocubes show large surface areas, which contribute to faster Na + diffusion kinetics. Unique pod‐like N‐doped carbon nanofibers not only serve as reinforcing frameworks to inhibit volume change but also improve the conductivity of CoNiSe 2 /PCNFs. Herein, the CoNiSe 2 /PCNFs electrode achieves a high capacity of 395.8 mAh g −1 at a current density of 0.1 A g −1 after 100 cycles and exhibits excellent cycling stability for 1000 cycles at a current density of 1.0 A g −1 with a capacity of 284.3 mAh g −1 . The novel structure and high electrochemical properties of CoNiSe 2 /PCNFs shed new light on developing high‐performance bimetallic selenides as SIB anodes.