Nitrogen-doped soft carbon frameworks built of well-interconnected nanocapsules enabling a superior potassium-ion batteries anode

Potassium-ion batteries (PIBs) have been regarded as one of the most promising alternatives to traditional lithium-ion batteries because of the low cost and abundant reserves of potassium resources. However, it is challenging to achieve suitable anode materials with long cycle life and high rate performance. Herein, nitrogen-doped soft carbon frameworks built of well-interconnected nanocapsules have been fabricated as facile and effective anodes for PIBs. The anode delivers a high specific capacity of 293 mAh g(-1) at 0.05 A g(-1) and 151 mAh g(-1) at 5 A g(-1) with a rate capability of 51.5%. It retains 85.5% capacity retention at 1 A g(-1) after 500 cycles. The excellent rate performance can be mainly ascribed to the high ionic and electronic conductivity, resulted from the ordered nitrogen-doped carbon clusters with enlarged interlayer distance. The interconnected hierarchically porous structure further promotes K+ diffusion kinetics.