Ultra-light and flexible pencil-trace anode for high performance potassium-ion and lithium-ion batteries

Engineering design of battery configurations and new battery system development are alternative approaches to achieve high performance batteries. A novel flexible and ultra-light graphite anode is fabricated by simple friction drawing on filter paper with a commercial 8B pencil. Compared with the traditional anode using copper foil as current collector, this innovative current-collector-free design presents capacity improvement of over 200% by reducing the inert weight of the electrode. The as-prepared pencil-trace electrode exhibits excellent rate performance in potassium-ion batteries (KIBs), significantly better than in lithium-ion batteries (LIBs), with capacity retention of 66% for the KIB vs. 28% for the LIB from 0.1 to 0.5 A g(-1). It also shows a high reversible capacity of similar to 230 mAh g(-1) at 0.2 A g(-1), 75% capacity retention over 350 cycles at 0.4 A g(-1) and the highest rate performance (based on the total electrode weight) among graphite electrodes for K+ storage reported so far. (C) 2017, Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.