Monoclinic lithium vanadium phosphate Li₃V₂(PO₄)₃ is a very promising cathode candidate for applications in Li-ion batteries, with a high operational voltage (~ 4 V vs. Li⁺/Li) and a high theoretical capacity of 197 mAh/g. However, the underlying electrochemical mechanism of monoclinic Li₃V₂(PO₄)₃ is not yet fully understood, due to its complexity. To gain more knowledge about the electrochemical performance of the monoclinic Li₃V₂(PO₄)₃, we perform density functional calculations of structural, electrochemical, electronic, and magnetic properties of Li_xV₂(PO₄)₃ for x = 3, 2, 1, based on the full-potential linearized augmented plane wave (FP-LAPW) method. The generalized gradient approximation corrected with the present work self-consistently calculated Hubbard parameter U (GGA+U method) shows that it can successfully reproduce the experimental average lithium intercalation voltage for the redox couple V⁴⁺/V³⁺ within 7% error, and within 2% error for the transition x: 3 ➔ 2. The present work method is fully ab initio and without any arbitrary parameters. In the literature, the existence of charge ordering in Li₂V₂(PO₄)₃ is subject to discrepancy. By analyzing the present calculated structural, magnetic, and electronic properties of Li₂V₂(PO₄)₃, the existence of charge ordering had been confirmed. The present work method sets the path for accurately predicting the redox potential of future lithium and sodium phosphate compounds for the next-generation batteries technology.

单斜晶系磷酸钒锂Li ₃ V ₂（PO ₄）₃是锂离子电池应用中非常有希望的阴极候选材料，具有高工作电压（〜4 V vs. Li ⁺ / Li）和197的高理论容量毫安/克 然而，由于其复杂性，单斜晶Li ₃ V ₂（PO ₄）₃的潜在电化学机理尚未完全理解。获得有关单斜晶Li ₃ V ₂（PO ₄）₃的电化学性能的更多知识，我们 基于全势线性化增强平面波（FP-LAPW），对x = 3、2、1的Li _x V ₂（PO ₄）₃进行结构，电化学，电子和磁性性质的密度泛函计算方法。用本工作自洽计算出的Hubbard参数U（GGA + U方法）校正后的广义梯度近似表明，它可以成功地将氧化还原对V ⁴⁺ / V ³⁺的实验平均锂嵌入电压复制到7％的误差内，转换x的误差在2％以内：3×2。本工作方法完全是从头开始的，没有任何任意参数。在文献中，Li ₂ V ₂（PO ₄）₃中电荷排序的存在存在差异。通过分析当前计算出的Li ₂ V ₂（PO ₄）_3的结构，磁性和电子性质，证实了电荷排序的存在。本工作方法为准确预测用于下一代电池技术的未来锂和磷酸钠化合物的氧化还原电位提供了途径。