非化学计量掺杂的LiNa_xV_3O_8水系锂离子电池负极材料

Non-stoichiometric Doped LiNa_xV_3O_8 as Anode Materials for Aqueous Lithium Ion Batteries

采用溶胶-凝胶法制备出非化学计量Na+掺杂的Li NaxV3O8材料。XRD分析表明,材料主相为Li V3O8层状结构;非化学计量的Na+掺杂可有效增大Li V3O8层状结构的层间距d,从而降低Li+在材料内部的扩散阻力。SEM图像显示材料形貌均匀,呈厚度约100 nm的薄片状,有效减小了Li+在材料内的扩散路径。充放电测试表明掺杂量为5%的材料表现出最佳的充放电可逆性,其最大放电比容量经过活化后可达117.6 m Ah/g,经50次循环后的放电比容量仍有67.6 m Ah/g。

Non-stoichiometric Na+doped LiNaxV308 materials are prepared by sol-gel method.XRD pattern shows that the main phase of the material has the LiV308 layered structure.The doping of nonstoichiometric Na+can significantly increase the d value of interlayer spacing,which reduces the diffusion resistance of Li+inside the material.The SEM images show that the material has a uniform morphology featured with flakes up to 100 nm in thickness.This leads to a shorter diffusion path of Li+inside the material.Charge and discharge tests show that sample with 5%doping has the best charge/discharge reversibility.The discharge capacity reaches 117.6 mAh/g after activation and 67.6 mAh/g after 50 cycles.