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-1 at 0.5 A g-1 and an ultrafast charge-discharge feature with a remarkable capacity of 340 mA h g-1 at an ultrahigh current density of 40 A g-1 and a superlong cycle life with a capacity retention of 93% after 10 000 cycles at 40 A g-1 . More importantly, when coupled with LiFePO4 cathode, the fabricated lithium-ion full cells also exhibit high capacity and excellent rate and cycling performances, highlighting the practicability of this NC@GF.
Keywords: 3D graphene frameworks; N-doped; high-performance anodes; lithium-ion batteries; ultrathin carbon layers.
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