The intermediate product VPO₄/C is synthesized via sol-gel method, then it is mixed with other raw materials and calcined to prepare Li_1-xK_xVPO₄F/C (x = 0, 0.005, 0.01, 0.02). Potassium with large ionic radius partially substitutes the lithium site and slightly increases the unit cell volume. The potassium dopant suppresses the formation of Li₃V₂(PO₄)₃ and reduces the particle agglomeration. The doped samples possess lower polarization and higher discharge plateau than the pristine LiVPO₄F/C, and Li_0.99K_0.01VPO₄F/C exhibits the best electrochemical performance. With 2.9 wt% amorphous carbon uniformly wrapping the surface, Li_0.99K_0.01VPO₄F/C delivers a reversible capacity of 140.9 mA h g^-1 at 0.12 C and maintains 98.3 mA h g^-1 at the charge/discharge rate of 10 C. Its specific discharge capacity with a retention of 96.13% decreases from 131.9 to 126.8 mA h g^-1 after 125 cycles at the charge/discharge rate of 1 C. The improvement of rate and cycling performance is ascribed to the decrease of charge transfer resistance (88.47 Ω) and the increase of Li⁺ diffusion coefficient (6.75 × 10⁻¹³ cm² s⁻¹), indicating that potassium doping facilitates the migration and diffusion of Li⁺ due to the expansion of Li⁺ pathway.

通过溶胶-凝胶法合成中间产物VPO ₄ / C，然后将其与其他原料混合并煅烧以制备Li _1-x K _x VPO ₄ F / C（x = 0、0.005、0.01、0.02）。离子半径大的钾会部分取代锂的位置，并会稍微增加单位电池的体积。钾掺杂剂抑制了Li ₃ V ₂（PO ₄）_3的形成并减少了颗粒的团聚。与原始LiVPO ₄ F / C和Li _0.99 K _0.01 VPO ₄相比，掺杂样品具有更低的极化和更高的放电平台。F / C表现出最佳的电化学性能。Li _0.99 K _0.01 VPO ₄ F / C用2.9 wt％的无定形碳均匀包裹在表面上，在0.12 C时可逆容量为140.9 mA h g ^-1，在10 C的充放电速率下可保持98.3 mA h g ^-1。在1 C的充放电速率下，经过125次循环后，其具有96.13％保留率的比放电容量从131.9降至126.8 mA hg ^-1。速率和循环性能的提高归因于电荷转移电阻的降低（88.47 Ω）和Li ⁺扩散系数的增加（6.75×10 ^-13  cm ²  s ^-1），表明由于Li ⁺途径的扩展，钾掺杂促进了Li ⁺的迁移和扩散。