Deposition-Induced Carbon Polymorph

摘要

Virtual Cathode Deposition (VCD) process transforms commercial graphite bulk material into a carbon polymorph film. Model suggesting carbon ion subsurface implantation is proposed to explain formation of the unique polymorph structure of carbon. Detailed structural characterisation reveals controllably induced packing polymorphism, high surface area (～ 2100 m[2] g[-1]), morphology with predominantly meso- and micro-porosity in a disordered carbon matrix encompassing nano-sized sp[2]-clusters (average size ～ 20 nm) cross-linked by a network of sp3-bonded atomic sites. The polymorph applied as Li-ion battery anode active material revealed first cycle specific capacity of up to 1250 mAh g[-1] and retaining >900 mAh g[-l] at 0.1C rate, which is significantly above the theoretical limit of lithium intercalation capacity for the graphite (372 mAh g[-1]). Excellent volumetric (—1400 Ah L[-1]) and areal capacity up to 4.2 mAh cm[-2] has been received with a 20 μm carbon film anode manufactured with an industrially scalable VCD process.