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

摘要

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 8 B 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 ～230 mAh g-1 at 0.2 A g-1, 75% capacity retention over350 cycles at 0.4 A g-1and the highest rate performance（based on the total electrode weight） among graphite electrodes for K+ storage reported so far.