School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
Nanotechnology. 2017 Mar 3;28(9):095402. doi: 10.1088/1361-6528/aa57b2. Epub 2017 Jan 9.
Germanium exhibits high charge capacity and high lithium diffusivity, both are the key requirements for electrode materials in high performance lithium ion batteries (LIBs). However, high volume expansion and segregation from the electrode during charge-discharge cycling have limited use of germanium in LIBs. Here, we demonstrate that ZnO decorated Ge nanoparticles (Ge@ZnO NPs) can overcome these limitations of Ge as an LIB anode material. We produced Ge NPs at high rates by laser pyrolysis of GeH, then coated them with solution phase synthesized ZnO NPs. Half-cell tests revealed dramatically enhanced cycling stability and higher rate capability of Ge@ZnO NPs compared to Ge NPs. Enhancements arise from the core-shell structure of Ge@ZnO NPs as well as production of metallic Zn from the ZnO layer. These findings not only demonstrate a new surface treatment for Ge NPs, but also provide a new opportunity for development of high-rate LIBs.
锗具有高电荷容量和高锂离子扩散率，这两者都是高性能锂离子电池（LIB）电极材料的关键要求。然而，在充放电循环过程中，由于体积膨胀大和与电极分离，限制了锗在 LIB 中的应用。在这里，我们证明了 ZnO 修饰的 Ge 纳米颗粒（Ge@ZnO NPs）可以克服 Ge 作为 LIB 阳极材料的这些限制。我们通过 GeH 的激光热解以高速率生产 Ge NPs，然后用溶液相合成的 ZnO NPs 对其进行包覆。与 Ge NPs 相比，半电池测试显示 Ge@ZnO NPs 的循环稳定性显著提高，倍率性能更高。这种增强来自 Ge@ZnO NPs 的核壳结构以及 ZnO 层中金属 Zn 的产生。这些发现不仅为 Ge NPs 提供了一种新的表面处理方法，而且为开发高倍率 LIB 提供了新的机会。
