Germanium-based materials attract more interest as anodes for lithium-ion batteries, stemming from their physical and chemical advantages. However, these materials inevitably undergo capacity attenuation caused by significant volumetric variation in repeated electrochemical processes. Herein, we designed 3D porous Ge/N-doped carbon nanocomposites by the encapsulation of 3D porous Ge in a nitrogen-doped carbon matrix (denoted as 3D porous Ge/NC). The 3D porous structure can accommodate the volume change during alloying/dealloying processes and improve the penetration of the electrolyte. Furthermore, the doping of N in the carbon framework could introduce more defects and active sites, which can also contribute to electron transportation and lithium-ion diffusion. The half-cell test found that at a current density of 1 C (1 C = 1600 mA h g⁻¹), the specific capacity stabilized at 917.9 mA h g⁻¹ after 800 cycles; and the specific capacity remained at 542.4 mA h g⁻¹ at 10 C. When assembled into a 3D porous Ge/NC//LiFePO₄ full cell, the specific capacity was stabilized at 101.3 mA h g⁻¹ for 100 cycles at a current density of 1 C (1 C = 170 mA h g⁻¹), and the cycle specific capacity was maintained at 72.6 mA h g⁻¹ at a high current density of 5 C. This work develops a low-cost, scalable and simple strategy to improve the electrochemical performance of these alloying type anode materials with huge volume change in the energy storage area.

中文翻译：

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可扩展合成封装在氮掺杂碳基质中的 3D 多孔锗作为锂离子电池的超长循环寿命阳极

由于其物理和化学优势，锗基材料作为锂离子电池的负极吸引了更多的兴趣。然而，这些材料不可避免地会因重复电化学过程中的显着体积变化而导致容量衰减。在此，我们通过将 3D 多孔 Ge 封装在氮掺杂碳基质（表示为 3D 多孔 Ge/NC）中来设计 3D 多孔 Ge/N 掺杂碳纳米复合材料。3D 多孔结构可以适应合金化/脱合金过程中的体积变化并提高电解质的渗透性。此外，在碳骨架中掺杂 N 可以引入更多的缺陷和活性位点，这也有助于电子传输和锂离子扩散。半电池测试发现，在电流密度为 1 C (1 C = 1600 mA hg^-1 )，800次循环后比容量稳定在917.9 mA hg ^-1；并且比容量在 10 C 下保持在 542.4 mA hg ^-1。当组装成 3D 多孔 Ge/NC//LiFePO ₄全电池时，比容量稳定在 101.3 mA hg ^-1并在电流密度为 100 次循环1 C (1 C = 170 mA hg ^-1 )，并且循环比容量在5 C 的高电流密度下保持在 72.6 mA hg ^-1。这项工作开发了一种低成本、可扩展和简单的策略来改善这些合金型负极材料的电化学性能在储能区域具有巨大的体积变化。