Tai, Z.Liu, Y.Zhang, Q.Zhou, T.Guo, Z.Liu, H.K.Dou, S.X.2021-09-282021-09-282017Green Energy & Environment, 2017; 2(3):278-2842468-02572468-0257https://hdl.handle.net/2440/132366Engineering 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 ∼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.en© 2017, Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Current-collector-free; flexible pencil-trace electrode; potassium-ion battery; lithium-ion battery; layer-by-layer interconnected architectureJournal article10.1016/j.gee.2017.04.0022021-09-28571487Guo, Z. [0000-0003-3464-5301]