Liu Yi-Lin, Yan Cheng, Wang Gui-Gen, Li Fei, Huang-Fu Jia-Shun, Wu Bo-Wen, Zhang Hua-Yu, Han Jie-Cai
Shenzhen Key Laboratory for Advanced Materials, Harbin Institute of Technology, Shenzhen 518055, People's Republic of China. Contributed equally to this work.
Nanotechnology. 2020 Apr 9;31(26):265405. doi: 10.1088/1361-6528/ab8149. Epub 2020 Mar 19.
Transition metal oxides have recently been demonstrated as highly attractive anodes for high-capacity lithium ion batteries, whose electrochemical properties could be further improved through rational architecture design and incorporating reliable conductive network. Herein, mesoporous γ-FeO spheres/graphene aerogel composites were synthesized via a solvothermal pathway followed by suitable annealing. Experimental results reveal the uniform mesoporous structure and well-dispersed γ-FeO spheres with the size of 300-400 nm embedded in the mesopores of the graphene aerogel network. Compared with α-FeO/graphene aerogel and pure γ-FeO, the as-synthesized composite delivers, at the first cycle, a high discharging capacity of 1080 mAh g at current density of 200 mA g. Even at much higher current density of 8000 mA g, satisfactory discharging capacities of 421.5 mAh g can still be achieved. Upon 100 charging-discharging cycles, the specific capacity of as high as 890.5 mAh g at 200 mA g is maintained. The enhanced electrochemical properties could be attributed to their favorable three-dimensional graphene aerogel network, which accounts for the improved structural stability and electronic conductivity of γ-FeO during the lithiation/delithiation process.
过渡金属氧化物最近已被证明是用于高容量锂离子电池的极具吸引力的负极材料，通过合理的结构设计和引入可靠的导电网络，其电化学性能可以得到进一步改善。在此，通过溶剂热法合成了介孔γ-FeO球/石墨烯气凝胶复合材料，随后进行了适当的退火处理。实验结果表明，在石墨烯气凝胶网络的介孔中嵌入了尺寸为300-400nm的均匀介孔结构且分散良好的γ-FeO球。与α-FeO/石墨烯气凝胶和纯γ-FeO相比，所合成的复合材料在第一个循环中，在200mA g的电流密度下具有1080mAh g的高放电容量。即使在高达8000mA g的更高电流密度下，仍可实现421.5mAh g的令人满意的放电容量。经过100次充放电循环后，在200mA g时仍可保持高达890.5mAh g的比容量。电化学性能的增强可归因于其良好的三维石墨烯气凝胶网络，这使得γ-FeO在锂化/脱锂过程中的结构稳定性和电子导电性得到改善。
