Fan Mengna, Yang Zhonghu, Lin Zhihua, Xiong Xunhui
Guangzhou Key Laboratory of Surface Chemistry of Energy Materials, New Energy Research Institute, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
Nanoscale. 2021 Feb 4;13(4):2368-2372. doi: 10.1039/d0nr07659g.
Great efforts, such as nano-structuring and carbon coating, have been devoted to addressing the poor rate performance of TiO2 anodes in lithium ion batteries, which is mainly caused by sluggish Li ion diffusion and poor electrical conductivity of the bulk material. However, the complicated fabrication processes make most of these strategies much low practical significance. Herein, a scalable and facile strategy based on sacrificial template-accelerated hydrolysis and polydopamine coating is proposed to manufacture uniform N-doped carbon-coated TiO2 hollow spheres. The nanostructured hollow structure can shorten the path of Li+ insertion/extraction in the electrode material. More importantly, the uniform carbon layer can improve the electronic conductivity of TiO2 during long-term cycling. Thus, a reversible capacity can be obtained of as high as 390.2 mA h g-1 at a current density of 0.1 A g-1. Furthermore, a high capacity of 166.3 mA h g-1 after 2000 cycles at 5.0 A g-1 shows that the carbon-coated TiO2 hollow spheres deliver good capacity retention and cycling performance.
人们已经做出了巨大努力，如纳米结构化和碳包覆，以解决锂离子电池中TiO₂负极倍率性能差的问题，这主要是由Li⁺扩散缓慢和块状材料的电导率差引起的。然而，复杂的制造工艺使得这些策略大多实际意义不大。在此，提出了一种基于牺牲模板加速水解和聚多巴胺包覆的可扩展且简便的策略，以制备均匀的N掺杂碳包覆TiO₂空心球。这种纳米结构的空心结构可以缩短电极材料中Li⁺嵌入/脱出的路径。更重要的是，均匀的碳层可以在长期循环过程中提高TiO₂的电子导电性。因此，在0.1 A g⁻¹ 的电流密度下可获得高达390.2 mA h g⁻¹ 的可逆容量。此外，在5.0 A g⁻¹ 下循环2000次后具有166.3 mA h g⁻¹ 的高容量，表明碳包覆TiO₂空心球具有良好的容量保持率和循环性能。
