关键词: 钠离子电池, Na₂MnSiO₄, 溶胶-凝胶法, 电化学性能

Abstract: As a promising cathode material for sodium ion batteries, pure phase Na₂MnSiO₄/C nanocomposite was successfully synthesized by a sol-gel method with a citric acid as a complex agent. The as prepared material was characterized by XRD, FTIR, SEM and TEM techniques. XRD and Rietveld refinement results indicated that the sample was indexed as monoclinic structure with space group of Pn. It was observed by SEM and TEM that the obtained product consisted of micro-scaled secondary particles, which were composed of NaMnSiO4 nanocrystallites and amorphous carbon network. More importantly, the uniform carbon network in the nanocomposite greatly enhanced the electronic conductivity of the material, thus, resulted in the impressive electrochemical performance. The electrochemical tests showed that the Na₂MnSiO₄/C could deliver a reversible capacity of 113 mAh·g^-1 (vs. Na⁺/Na) at a current density of 14 mA·g^-1 within 1.5 ~ 4.2 V when 1 mol·L^-1 NaClO₄ + PC was used as the electrolyte.

Key words: Sodium ion battery, Na2MnSiO4, sol-gel method, electrochemical performance