Physics

Kinetics

Nanotechnology

Electrode

Carbon nanofiber

Organic chemistry

Potassium

Anode

Composite number

Endocrinology

Engineering

Carbon fibers

Physical chemistry

Composite material

Chemistry

Metallurgy

Materials science

Lithium (medication)

Prussian blue

Cathode

Quantum mechanics

Chemical engineering

Carbon nanotube

Electrochemistry

Nitrogen

Medicine

Nanofiber

Nature Communications

Potassium-ion batteries are a promising alternative to lithium-ion batteries. However, it is challenging to achieve fast charging/discharging and long cycle life with the current electrode materials because of the sluggish potassiation kinetics. Here we report a soft carbon anode, namely highly nitrogen-doped carbon nanofibers, with superior rate capability and cyclability. The anode delivers reversible capacities of 248 mAh g-1 at 25 mA g-1 and 101 mAh g-1 at 20 A g-1, and retains 146 mAh g-1 at 2 A g-1 after 4000 cycles. Surface-dominated K-storage is verified by quantitative kinetics analysis and theoretical investigation. A full cell coupling the anode and Prussian blue cathode delivers a reversible capacity of 195 mAh g-1 at 0.2 A g-1. Considering the cost-effectiveness and material sustainability, our work may shed some light on searching for K-storage materials with high performance.

Highly nitrogen doped carbon nanofibers with superior rate capability and cyclability for potassium ion batteries