论文标题
铜磷化物作为锂离子电池转化阳极的计算研究
Computational Investigation of Copper Phosphides as Conversion Anodes for Lithium-Ion Batteries
论文作者
论文摘要
使用第一原理结构搜索使用密度官能理论（DFT），我们确定了一种新颖的$ fm \ bar {3} m $ cu $ _2 $ p和两个低洼的稳态结构的相位，一个$ i \ bar {4} 3d $ - cu $ -cu $ _3 $ P阶段，以及$ cm $ $ $ cu $ $ $ $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _111111111111111111111111111111EK} 1111} {1111} {1111} {1111}。新颖$ cm $ - cu $ _3 $ p $ _ {11} $ phase的计算成对分配功能显示了与实验确定的$ cm $ -cu $ _2 $ _2 $ p $ _7 $ apeas的结构相似性。 The relative stability of all Cu--P phases at finite temperatures is determined by calculating the Gibbs free energy using vibrational effects from phonon modes at 0 K. From this, a finite-temperature convex hull is created, on which $Fm\bar{3}m$--Cu$_2$P is dynamically stable and the Cu$_{3-x}$P ($x < 1$) defect phase $Cmc2_1$--Cu$_8$P$_3$ remains metastable (within 20 meV/atom of the convex hull) across a temperature range from 0 K to 600 K. Both CuP$_2$ and Cu$_3$P exhibit theoretical gravimetric capacities higher than contemporary graphite anodes for Li-ion batteries;预测的Cu $ _2 $ P相具有508 mAh/g的理论重量量，作为锂离子电池电极，大于Cu $ _3 $ P（363 mAh/g）和石墨（372 mAh/g）。 Cu $ _2 $ p也预计是非磁性和金属的，这应该促进阳极中的有效电子传输。 Cu $ _2 $ p的有利属性作为金属，大容量的材料，建议将其用作锂离子电池的未来转换阳极；在完整循环过程中，体积膨胀为99％，Cu $ _2 $ p阳极可能比Cu-P系统中的其他转换阳极更耐用，其体积扩展大于150％。
Using first principles structure searching with density-functional theory (DFT) we identify a novel $Fm\bar{3}m$ phase of Cu$_2$P and two low-lying metastable structures, an $I\bar{4}3d$--Cu$_3$P phase, and a $Cm$--Cu$_3$P$_{11}$ phase. The computed pair distribution function of the novel $Cm$--Cu$_3$P$_{11}$ phase shows its structural similarity to the experimentally identified $Cm$--Cu$_2$P$_7$ phase. The relative stability of all Cu--P phases at finite temperatures is determined by calculating the Gibbs free energy using vibrational effects from phonon modes at 0 K. From this, a finite-temperature convex hull is created, on which $Fm\bar{3}m$--Cu$_2$P is dynamically stable and the Cu$_{3-x}$P ($x < 1$) defect phase $Cmc2_1$--Cu$_8$P$_3$ remains metastable (within 20 meV/atom of the convex hull) across a temperature range from 0 K to 600 K. Both CuP$_2$ and Cu$_3$P exhibit theoretical gravimetric capacities higher than contemporary graphite anodes for Li-ion batteries; the predicted Cu$_2$P phase has a theoretical gravimetric capacity of 508 mAh/g as a Li-ion battery electrode, greater than both Cu$_3$P (363 mAh/g) and graphite (372 mAh/g). Cu$_2$P is also predicted to be both non-magnetic and metallic, which should promote efficient electron transfer in the anode. Cu$_2$P's favorable properties as a metallic, high-capacity material suggest its use as a future conversion anode for Li-ion batteries; with a volume expansion of 99% during complete cycling, Cu$_2$P anodes could be more durable than other conversion anodes in the Cu--P system with volume expansions greater than 150%.
