ABSTRACT

A Mo-doping LiFe_1-xMo_xPO₄/C cathode material was synthesized via carbothermal reduction route, and the effect of the content of Mo on the structure and electrochemical performance of LiFePO₄/C was studied. XRD results revealed doping of Mo did not change the olivine structure of LiFePO₄/C, but also formed the Li⁺ vacancies, which contribute to increase the diffusion rate of Li⁺. The experimental results further demonstrated that among the Mo-doping samples, the LiFe_0.98Mo_0.02PO₄/C exhibited the best cycle performance and rate performance. After 100 cycles at 0.1 C, its discharge specific capacity reached 143.2 mAh·g⁻¹, which was about 10 mAh·g⁻¹ higher than that of pure phase LiFePO₄/C. The capacity retention rate was 98%. When cycling at a rate of up to 5 C, the discharge specific capacity of LiFe_0.98Mo_0.02PO₄/C can still be maintained above 90 mAh·g⁻¹, indicating that Mo doping was an effective method to improve LiFePO₄/C electrochemical performance.

摘要

通过碳热还原法合成了一种Mo掺杂的LiFe _1-x Mo _x PO ₄ / C正极材料，研究了Mo含量对LiFePO ₄ / C结构和电化学性能的影响。XRD结果表明，Mo的掺杂并没有改变LiFePO ₄ / C的橄榄石结构，而是形成了Li ⁺空位，这有助于提高Li ⁺的扩散速率。实验结果进一步表明，在钼掺杂样品中，LiFe _0.98 Mo _0.02 PO ₄/ C表现出最佳的循环性能和速率性能。在0.1C下100次循环后，其放电比容量达到143.2mAh·g ^-1，比纯相LiFePO ₄ / C高约10mAh·g ^-1。容量保持率为98％。当以高达5 C的速率循环时，LiFe _0.98 Mo _0.02 PO ₄ / C的放电比容量仍可保持在90 mAh·g ^-1以上，表明Mo掺杂是改善LiFePO ₄ / C的有效方法。电化学性能。