Novel binder-free carbon anode for high capacity Li-ion batteries

초록

Novel binder-free, high capacity carbon-based anodes were manufactured using Virtual Cathode Deposition technique in an industrially scalable process. The deposition process transformed a commercial graphite target material into a novel carbon polymorph coating, which was used as Li-ion battery anode. Such anodes displayed first cycle specific capacity of -1250 mAh g-1 and retained a capacity of more than 900 mAh g-1 at 0.1 C rate and more than 600 mAh g-1 at 0.5 A g-1 rate during cycling. Coulombic efficiencies above 99.5% were attained for 500 cycles. The anodes showed excellent volumetric (>1400 Ah L-1) and areal capacity (-4.5 mAh cm-2). Detailed structural characterisation revealed controllably induced packing polymorphism and high surface area (-2100 m2 g-1). The hierarchical architecture of the coatings was composed predominantly of meso- and macropores observed in a disordered carbon matrix encompassing nano-sized sp2-clusters (average size - 15?20 nm) cross-linked by a network of sp3-bonded atomic sites. A growth model based on the subsurface implantation mechanism was adopted to explain the formation of this unique structure responsible for the measured high specific capacity and good Coulombic efficiency.

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