Huang Yanshan, Li Ke, Yang Guanhui, Aboud Mohamed F Aly, Shakir Imran, Xu Yuxi
State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai, 200433, China.
Sustainable Energy Technologies Center, College of Engineering Center, King Saud University, Riyadh, 11421, Kingdom of Saudi Arabia.
Small. 2018 Mar;14(13):e1703969. doi: 10.1002/smll.201703969. Epub 2018 Jan 24.
The designable structure with 3D structure, ultrathin 2D nanosheets, and heteroatom doping are considered as highly promising routes to improve the electrochemical performance of carbon materials as anodes for lithium-ion batteries. However, it remains a significant challenge to efficiently integrate 3D interconnected porous frameworks with 2D tunable heteroatom-doped ultrathin carbon layers to further boost the performance. Herein, a novel nanostructure consisting of a uniform ultrathin N-doped carbon layer in situ coated on a 3D graphene framework (NC@GF) through solvothermal self-assembly/polymerization and pyrolysis is reported. The NC@GF with the nanosheets thickness of 4.0 nm and N content of 4.13 at% exhibits an ultrahigh reversible capacity of 2018 mA h g at 0.5 A g and an ultrafast charge-discharge feature with a remarkable capacity of 340 mA h g at an ultrahigh current density of 40 A g and a superlong cycle life with a capacity retention of 93% after 10 000 cycles at 40 A g . More importantly, when coupled with LiFePO cathode, the fabricated lithium-ion full cells also exhibit high capacity and excellent rate and cycling performances, highlighting the practicability of this NC@GF.
具有三维结构、超薄二维纳米片和杂原子掺杂的可设计结构,被认为是提高碳材料作为锂离子电池负极电化学性能的极有前景的途径。然而,将三维互连多孔框架与二维可调杂原子掺杂超薄碳层有效整合以进一步提升性能,仍然是一项重大挑战。在此,报道了一种通过溶剂热自组装/聚合和热解原位包覆在三维石墨烯框架(NC@GF)上的由均匀超薄氮掺杂碳层组成的新型纳米结构。纳米片厚度为4.0 nm且氮含量为4.13 at%的NC@GF在0.5 A g下表现出2018 mA h g的超高可逆容量,在40 A g的超高电流密度下具有340 mA h g的显著容量的超快充放电特性,以及在40 A g下10000次循环后容量保持率为93%的超长循环寿命。更重要的是,当与磷酸铁锂正极耦合时,所制备的锂离子全电池也表现出高容量以及优异的倍率和循环性能,突出了这种NC@GF的实用性。