Qin Wei, Lu Wen-Cai, Xue Xu-Yan, Ho Kai-Ming, Wang Cai-Zhuang
College of Physics, Qingdao University, Qingdao 266071, China.
State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, Qingdao 266071, China.
Nanomaterials (Basel). 2021 Dec 15;11(12):3397. doi: 10.3390/nano11123397.
The model of a graphene (Gr) sheet putting on a silicon (Si) substrate is used to simulate the structures of Si microparticles wrapped up in a graphene cage, which may be the anode of lithium-ion batteries (LIBS) to improve the high-volume expansion of Si anode materials. The common low-energy defective graphene (-Gr) structures of DV5-8-5, DV555-777 and SV are studied and compared with perfect graphene (-Gr). First-principles calculations are performed to confirm the stable structures before and after Li penetrating through the Gr sheet or graphene/Si-substrate (Gr/Si) slab. The climbing image nudged elastic band (CI-NEB) method is performed to evaluate the diffusion barrier and seek the saddle point. The calculation results reveal that the -Gr greatly reduces the energy barriers for Li diffusion in Gr or Gr/Si. The energy stability, structural configuration, bond length between the atoms and layer distances of these structures are also discussed in detail.
采用石墨烯（Gr）片放置在硅（Si）衬底上的模型来模拟包裹在石墨烯笼中的硅微粒结构，这可能是锂离子电池（LIBs）的阳极，以改善硅阳极材料的高体积膨胀。研究了常见的低能缺陷石墨烯（-Gr）结构DV5-8-5、DV555-777和SV，并与完美石墨烯（-Gr）进行了比较。进行第一性原理计算以确认锂穿透Gr片或石墨烯/硅衬底（Gr/Si）板前后的稳定结构。采用爬山图像弹性带（CI-NEB）方法评估扩散势垒并寻找鞍点。计算结果表明，-Gr大大降低了锂在Gr或Gr/Si中扩散的能垒。还详细讨论了这些结构的能量稳定性、结构构型、原子间键长和层间距。
