Lu Jijun, Wang Dong, Liu Junhao, Qian Guoyu, Chen Yanan, Wang Zhi
Key Laboratory of Green Process and Engineering, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences Beijing 100190 P. R. China
School of Chemical Engineering, University of Chinese Academy of Sciences Beijing 100039 P. R. China.
Nanoscale Adv. 2020 May 25;2(8):3222-3230. doi: 10.1039/d0na00297f. eCollection 2020 Aug 11.
The huge volume variation and the unstable solid electrolyte interface (SEI) of Si (Si) during the lithiation and delithiation process severely obstruct its practical application as lithium-ion battery anodes. Here, we design and fabricate a hollow structure of double-layer hybrid carbon nanocage encapsulated Si nanoparticles to address these challenges. The double-layer hybrid carbon-Si nanoarchitecture is obtained by integrating electrostatic self-assembly, seed-induced growth and heterogeneous shrinkage. The internal layer of hollow N-doped carbon of the hybrid nanoarchitecture (Si@H-NC@GC) provides limited inner space for controlling volume changes of Si nanoparticles, while the outer graphite carbon layer facilitates the formation of a stable SEI. When evaluated as anode materials for LIBs, the Si@H-NC@GC nanoarchitecture exhibits greatly enhanced electrochemical performance compared with the bare Si, Si@NC and H-NC@GC electrodes. Notably, Si@H-NC@GC delivers a reversible capacity retention of 92.5% after 550 cycles at a high current density of 1 A g and a high capacity of 1081 mA h g after 500 cycles at 0.5 A g.
硅（Si）在锂化和脱锂过程中巨大的体积变化以及不稳定的固体电解质界面（SEI）严重阻碍了其作为锂离子电池负极的实际应用。在此，我们设计并制备了一种双层混合碳纳米笼封装硅纳米颗粒的中空结构，以应对这些挑战。这种双层混合碳 - 硅纳米结构是通过整合静电自组装、种子诱导生长和异质收缩而获得的。混合纳米结构（Si@H - NC@GC）的中空氮掺杂碳内层为控制硅纳米颗粒的体积变化提供了有限的内部空间，而外层石墨碳层则有助于形成稳定的SEI。当作为锂离子电池的负极材料进行评估时，与裸硅、Si@NC和H - NC@GC电极相比，Si@H - NC@GC纳米结构表现出大大增强的电化学性能。值得注意的是，Si@H - NC@GC在1 A g的高电流密度下经过550次循环后可逆容量保持率为92.5%，在0.5 A g下经过500次循环后具有1081 mA h g的高容量。
