Zeng Tianbiao, Feng Dong, Peng Qimeng, Liu Qi, Xi Guocui, Chen Gang
State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065, China.
College of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054, China.
ACS Appl Mater Interfaces. 2021 Apr 7;13(13):15178-15189. doi: 10.1021/acsami.0c22616. Epub 2021 Mar 23.
Among the germanium-based compounds, GeTe is a promising anode candidate that exhibits high theoretical capacity (856 mAh g vs Li/Li and 401 mAh g vs Na/Na) and low volume expansion during an ion intercalation/deintercalation process. Nevertheless, achieving good dispersion of metal-like GeTe in anode materials remains a significant challenge. Herein, hybrid GeTe/graphene (GeTe/G) is proposed as a highly efficient anode for LiBs and SiBs by facile ball milling. Pulverized GeTe is effectively anchored on peeled graphene sheets that can accelerate Li transport in electrodes as predicted by theoretical calculations and thus result in improved overall electrochemical performance. For instance, GeTe/G possesses a high reversible capacity of 478 mAh g under 0.1 A g in the 300th cycle. Moreover, by further cross-linking the GeTe/G using carbon nanotube (CNT) and carbon nanofiber pyrolysis from cotton cellulose, the as-prepared three-dimensional (3D) flexible anode possesses macropores that acted as positive channels favorably for ion transport. Remarkably, the as-prepared flexible 3D GeTe/G/CNT electrode with a thickness of 1050 μm exhibits a high reversible capacity of 451.4 mAh g (4.38 mAh cm) vs Li/Li and 372.5 mAh g (2.08 mAh cm) vs Na/Na, respectively, in the second cycle under 0.1 A g. These results shed some light on the direct application of 3D flexible carbon sponge electrodes in high-performance LiBs/SiBs.
在锗基化合物中，GeTe是一种很有前景的负极候选材料，它在离子嵌入/脱嵌过程中表现出高理论容量（相对于Li/Li为856 mAh g，相对于Na/Na为401 mAh g）和低体积膨胀。然而，在负极材料中实现类金属GeTe的良好分散仍然是一个重大挑战。在此，通过简便的球磨法制备了GeTe/石墨烯（GeTe/G）复合材料，并将其作为锂离子电池和钠离子电池的高效负极。正如理论计算所预测的那样，粉碎后的GeTe有效地锚定在剥离的石墨烯片上，这可以加速电极中的锂传输，从而提高整体电化学性能。例如，在0.1 A g的电流密度下，GeTe/G在第300次循环中具有478 mAh g的高可逆容量。此外，通过使用碳纳米管（CNT）和棉纤维素热解得到的碳纳米纤维对GeTe/G进行进一步交联，制备出的三维（3D）柔性负极具有大孔，这些大孔有利于离子传输。值得注意的是，制备的厚度为1050 μm的柔性3D GeTe/G/CNT电极在0.1 A g的电流密度下的第二次循环中，相对于Li/Li分别表现出451.4 mAh g（4.38 mAh cm）的高可逆容量，相对于Na/Na表现出372.5 mAh g（2.08 mAh cm）的高可逆容量。这些结果为3D柔性碳海绵电极在高性能锂离子电池/钠离子电池中的直接应用提供了一些启示。
