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

Abstract

Abstract 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\u202fmAh\u202fg-1 and retained a capacity of more than 900\u202fmAh\u202fg-1 at 0.1\u202fC rate and more than 600\u202fmAh\u202fg-1 at 0.5\u202fA\u202fg-1 rate during cycling. Coulombic efficiencies above 99.5% were attained for 500 cycles. The anodes showed excellent volumetric (>1400\u202fAh\u202fL-1) and areal capacity (~4.5\u202fmAh\u202fcm-2). Detailed structural characterisation revealed controllably induced packing polymorphism and high surface area (~2100\u202fm2 g-1). The hierarchical architecture of the coatings was composed predominantly of meso- and macro-pores observed in a disordered carbon matrix encompassing nano-sized sp2-clusters (average size\u202f~\u202f15–20\u202fnm) 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.