Bismuth (III) (Bi³⁺) and chloride (Cl⁻) ion co-doped Li₃V_1·97Bi_0·03(PO₄)_3−x Cl _x /carbon (C) compounds (x = 0·03, 0·05, 0·07, 0·09) were prepared by way of a simple sol–gel method. The X-ray diffraction patterns proved that a small amount of bismuth (III) and chloride ion doping does not change the crystal structure of lithium vanadium phosphate (Li₃V₂(PO₄)₃). Charge/discharge results showed that bismuth (III) and chloride ion co-doped samples exhibited higher initial capacities than lithium vanadium phosphate/carbon. Li₃V_1·97Bi_0·03(PO₄)_2·95Cl_0·05/carbon demonstrated the highest capacity of 188 mAh/g at 0·1 C. The cycling performance at 1 C showed that the capacity retention of Li₃V_1·97Bi_0·03(PO₄)_2·95Cl_0·05/carbon reaches 81·31% after 300 cycles. Electrochemical impedance spectroscopy and cyclic voltammetry testing indicated that Li₃V_1·97Bi_0·03(PO₄)_2·95Cl_0·05 has the smallest charge-transfer resistance and the largest lithium-ion (Li⁺) diffusion coefficient. The improvement can be assigned to the enhanced kinetics of lithium ions, reduction in polarization and decreased charge-transfer resistance of the electrode.

中文翻译：

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Bi3 +和Cl−共掺杂的Li3V2（PO4）3作为锂离子电池阴极的高性能

铋（III）的（Bi ³⁺）和氯化（氯^- ）离子共掺杂锂₃ V _1·97的Bi _0·03（PO ₄）_{3- X} 氯_X /碳（C）化合物（X = 0·03 （0·05、0·07、0·09）是通过简单的溶胶-凝胶法制备的。X射线衍射图谱表明，少量的铋（III）和氯离子掺杂不会改变磷酸锂钒（Li ₃ V ₂（PO ₄）₃）的晶体结构。 ）。充电/放电结果表明，铋（III）和氯离子共掺杂的样品显示出比磷酸锂钒/碳更高的初始容量。Li ₃ V _1·97 Bi _0·03（PO ₄）_2·95 Cl _0·05 /碳在0·1 C时显示最高容量188 mAh /g。1C的循环性能表明其容量保持率Li ₃ V _1·97 Bi _0·03（PO ₄）_2·95 Cl _0·05 /碳经过300个循环后达到81·31％。电化学阻抗谱和循环伏安测试表明Li ₃ V _1·97Bi _0·03（PO ₄）_2·95 Cl _0·05具有最小的电荷转移电阻和最大的锂离子（Li ⁺）扩散系数。改善可以归因于增强的锂离子动力学，极化的减少和电极的电荷转移电阻的降低。