A three-dimensional Ge@C anode with a hollow and micro/nano structure for high-capacity lithium-ion battery

• Published in: Journal of energy storage Vol. 95; p. 112620
• Main Authors: Xu, Guangzheng, Zhu, Chengyu, Mao, Jianjiang, Zhao, Jinyang, Li, Xinxin, Cheng, Fei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2024
• Subjects: Anode; Hollow structure; Lithium-ion battery; Zif-8; Hollow structure; Lithium-ion battery; Anode; Ge; Zif-8
• ISSN: 2352-152X
• DOI: 10.1016/j.est.2024.112620

Aiming at the key issues of low intrinsic conductivity and large volume expansion during the cycling existed in high-capacity Ge anode material system, a micro/nano structured Ge@C hybrid material was designed and prepared through a facile and controllable method. The as-prepared micron conductive cage with a dodecahedral structure is composed of interconnected ultra-thin walled Ge nanotubes encapsulated in the porous N-containing carbon network, which can not only reserve more buffer space for the volume expansion of Ge and assist in building a stable SEI film during the cycling, improves the conductivity and stability of the material, but also provide a rich and penetrating channel for the transmission of ions, realizing high dynamics. When applied to the anode of lithium-ion battery, the three-dimensional micro/nano structured germanium-based hybrid material (Ge-3D@C) delivers a high initial specific capacity of 1500 mAh g−1 at 0.2 A g−1, and after 350 cycles, it can still maintain a high reversible specific capacity of 1147 mAh g−1. Even at high current densities of 1 A g−1 and 2 A g−1, high reversible specific capacities of 752 and 631 mAh g−1 can still be obtained. Importantly, the rational design can be used to prepare Ge hybrids doped with other metals or metal oxides, as well as different structures, by adjusting the layer materials and the types of germanates, so as to adapt to different application environments. [Display omitted] •Hydrothermal-carbon thermal reduction route is proposed using Zn2GeO4 as precursor.•A micro/nano Ge anode is fabricated and effective carbon modification is achieved.•Interconnected thin walled Ge nanotubes are encapsulated in ZIF-8 derived carbon.•A penetrating channel for ion transmission and high conductivity is achieved.•An enhanced capacity of 1147 mAh g−1 at 0.2 A g−1 is maintained after 350 cycles.