Ultrathin Carbon Nanosheets for Highly-efficient Capacitive K-ion and Zn-ion Storage

11 June 2020, Version 2
This content is a preprint and has not undergone peer review at the time of posting.


Porous carbon has attracted extensive attentions as the electrode material for various energy storage devices considering its advantages like high theoretical capacitance/capacity, high conductivity, low cost and earth abundant inherence. However, there still exists some disadvantages limiting its further applications, such as the tedious fabrication process, limited metal-ion transport kinetics and undesired structure deformation at harsh electrochemical conditions. Herein, we report a facile strategy, with calcium gluconate firstly reported as the carbon source, to fabricate ultrathin porous carbon nanosheets. The as-prepared Ca-900 electrode delivers excellent K-ion storage performance including high reversible capacity (430.7 mAh g-1), superior rate capability (154.8 mAh g-1 at an ultrahigh current density of 5.0 A g-1) and ultra-stable long-term cycling stability (a high capacity retention ratio of ~81.2% after 4000 cycles at 1.0 A g-1). Similarly, when being applied in Zn-ion capacitors, the Ca-900 electrode also exhibits an ultra-stable cycling performance with ~90.9% capacity retention after 4000 cycles at 1.0 A g-1, illuminating the applicable potentials. Moreover, the origin of the fast and smooth metal-ion storage is also revealed by carefully designed consecutive CV measurements. Overall, considering the facile preparation strategy, unique structure, application flexibility and in-depth mechanism investigations, this work will deepen the fundamental understandings and boost the commercialization of high-efficient energy storage devices like potassium-ion/sodium-ion batteries, zinc-ion batteries/capacitors and aluminum-ion batteries.


In situ self-template fabrication strategy
Ultrathin porous carbon nanosheets
Potassium-ion batteries
Zinc-ion hybrid capacitors
Capacitive energy storage

Supplementary materials

Supplementary material


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