Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University , Beijing 100084, P. R. China.
ACS Nano. 2017 Jun 27;11(6):5530-5537. doi: 10.1021/acsnano.7b00557. Epub 2017 Jun 14.
Sodium-ion batteries offer an attractive option for potential low cost and large scale energy storage due to the earth abundance of sodium. Red phosphorus is considered as a high capacity anode for sodium-ion batteries with a theoretical capacity of 2596 mAh/g. However, similar to silicon in lithium-ion batteries, several limitations, such as large volume expansion upon sodiation/desodiation and low electronic conductance, have severely limited the performance of red phosphorus anodes. In order to address the above challenges, we have developed a method to deposit red phosphorus nanodots densely and uniformly onto reduced graphene oxide sheets (P@RGO) to minimize the sodium ion diffusion length and the sodiation/desodiation stresses, and the RGO network also serves as electron pathway and creates free space to accommodate the volume variation of phosphorus particles. The resulted P@RGO flexible anode achieved 1165.4, 510.6, and 135.3 mAh/g specific charge capacity at 159.4, 31878.9, and 47818.3 mA/g charge/discharge current density in rate capability test, and a 914 mAh/g capacity after 300 deep cycles in cycling stability test at 1593.9 mA/g current density, which marks a significant performance improvement for red phosphorus anodes for sodium-ion chemistry and flexible power sources for wearable electronics.
钠离子电池由于钠在地壳中的丰富度而成为具有成本效益和大规模储能的有吸引力的选择。红磷被认为是具有 2596mAh/g 理论容量的钠离子电池的高容量阳极。然而，与锂离子电池中的硅类似，几个限制因素，如在吸钠/脱钠过程中的大体积膨胀和低电子电导率，严重限制了红磷阳极的性能。为了解决上述挑战，我们开发了一种将红磷纳米点密集均匀地沉积在还原氧化石墨烯片上的方法（P@RGO），以最小化钠离子扩散长度和吸钠/脱钠应力，并且 RGO 网络还用作电子路径并创造自由空间来容纳磷颗粒的体积变化。所得到的 P@RGO 柔性阳极在倍率性能测试中在 159.4、31878.9 和 47818.3 mA/g 的充放电电流密度下分别实现了 1165.4、510.6 和 135.3 mAh/g 的比电荷容量，在 1593.9 mA/g 的电流密度下经过 300 次深度循环后仍具有 914 mAh/g 的容量，这标志着红磷阳极在钠离子化学和用于可穿戴电子设备的柔性电源方面的性能有了显著提高。
