[论文解读] Phosphorene as an Anode Material for High Performance Lithium-Ion Battery: First Principle Study and Experimental Measurement

Congyan Zhang, George W. Anderson+3 more|arXiv (Cornell University)|Jul 1, 2016

2D Materials and Applications被引用 4

一句话总结

本研究通过第一性原理计算与实验验证，探究黑磷作为锂离子电池高性能负极材料的潜力。研究揭示了沿锯齿形方向的超快、各向异性的锂扩散行为，并预测其理论容量可达865 mAh/g，实验测得50次循环后可逆容量为453 mAh/g，表明即使在高锂化程度（x = 1）下也具有结构可逆性且无锂簇生成。

ABSTRACT

The prospects of phosphorene as an anode material for high performance Li-ion battery was systematically investigated from the first principle calculations and experimental measurements. The diffusion energy barriers of a Li atom moving along various orientations on phosphorene layer were calculated from the Li adsorption energy landscape. It was found that the diffusion mobility of a Li atom along the zigzag direction in the valley of phosphorene could be about 7 to 11 orders of magnitude faster than that along the other directions, indicating its ultrafast and anisotropic diffusivity. The lithium insertion in phosphorene was studied considering various LinP16 configurations (n=1~16). It was found that phosphorene could accommodate up to one Li per P atom (i.e., Li16P16), and the predicted theoretical value of the Li capacity for a single layered phosphorene can reach about 865 mAh/g. Our experimental measurement on the Li capacity for a network of a few layered phosphorene can reach a reversible stable value of ~ 453 mAh/g even after 50 cycles. In particular, it was found that, even at the high Li concentration (e.g., x = 1 in LixP), there was no Li clustering and the structure of phosphorene is reversible during the lithium intercalation. Our results clearly show that phosphorene has promise as a novel anode material for high performance Li-ion batteries.

研究动机与目标

• 评估黑磷作为锂离子电池高容量负极材料的潜力。
• 理解锂原子在黑磷表面的扩散动力学及其各向异性行为。
• 确定黑磷的最大锂存储容量，并评估其在锂化过程中的结构稳定性。
• 通过实验测量可逆容量与循环稳定性，验证理论预测的可行性。

提出的方法

• 采用第一性原理密度泛函理论（DFT）计算，获得黑磷上锂吸附能的分布图。
• 绘制黑磷中不同晶向（锯齿形与扶手椅形）的锂扩散路径及能垒。
• 评估多种Li_xP_16结构（x = 1至16）以确定最大锂化容量与结构稳定性。
• 对少层黑磷网络进行实验测量，以确定其可逆锂容量与循环性能。
• 结合计算与实验数据，分析锂化过程中的结构演变，评估其可逆性及无相分离现象。
• 将理论预测与实验结果进行对比，验证黑磷作为高性能负极材料的可行性。

实验结果

研究问题

• RQ1 锂原子在黑磷上的扩散行为如何？其随晶向的变化特征是什么？
• RQ2 单层黑磷的最大理论锂存储容量是多少？
• RQ3 在深度锂化（最高至Li16P16）过程中，黑磷的结构完整性如何变化？
• RQ4 黑磷能否在多次循环中保持可逆的锂插入与脱出，而无退化或锂簇生成？
• RQ5 实验结果与第一性原理预测在容量与稳定性方面的一致性程度如何？

主要发现

• 黑磷中沿锯齿形方向的锂扩散速率比其他方向快7至11个数量级，表明其具有强烈的各向异性扩散特性。
• 单层黑磷的理论比容量可达865 mAh/g，对应每个P原子吸附一个Li原子（Li16P16）。
• 对少层黑磷的实验测量显示，经过50次充放电循环后，其可逆容量稳定在约453 mAh/g。
• 即使在高锂化程度下（如x = 1时的LixP），也未观察到锂簇生成，表明锂化过程具有高度均匀性。
• 黑磷在锂化与脱锂过程中结构保持可逆，无不可逆相变或结构退化。
• 理论预测与实验结果高度一致，证实黑磷是高性能锂离子电池极具前景的负极材料。