A Facile Carbon Quantum Dot‐Modified Reduction Approach Towards Tunable Sb@CQDs Nanoparticles for High Performance Sodium Storage

Abstract Antimony (Sb) has considerable specific capacity as an anode material for sodium‐ion batteries. However, the large volume expansion during alloying/dealloying with Na⁺ leads to poor cycling stability. Herein, we report the synthesis of Sb@carbon quantum dots (Sb@CQDs) composite via a facile one‐step reduction approach at room temperature. CQDs can modify the nucleation and growth of Sb particles during the reduction process and thus tune the size of Sb. Sb@CQDs particles with size of ∼7 nm can relieve the volume expansion and reduce the diffusion distance for sodium ions. Moreover, the residual CQDs in the obtained composite enhance the electronic conductivity. Benefited from the modification of CQDs, the Sb@CQDs composite delivers high specific capacity of 635 mA h g⁻¹ at 0.1 A g⁻¹ and 334 mA h g⁻¹ at 2 A g⁻¹.