Constructing volcanic-like mesoporous hard carbon with fast electrochemical kinetics for potassium-ion batteries and hybrid capacitors

Potassium-ion batteries are considered as one of safe and low-cost alternatives to the traditional lithium-ion batteries. However, the sluggish potassium ion kinetics, drastic volume variation and inferior cyclic reversibility hinder the further development for the commercial applications. Herein, a new type of polyimide-inspired volcanic rock-like carbon is synthesized by pyrolyzing N/O-rich polymer precursor of polymeric 1, 4, 5, 8-Naphthalenetetracarboxylic dianhydride (PNTCDA). The synergetic effect of the mesoporous construction, the prominent capacitance and the ameliorated conductivity endows PNTCDA@900 with boosted potassium-ion electrochemical properties. As anodes for PIBs, the discharge capacity of 185.3 mAh g −1 can be achievable after 100 cycles at a current density of 0.05 A g −1 , and the superior reversible capacity of 81 mAh g −1 is obtained even after 4000 cycles at a high current density of 2 A g −1 . The cell can be operated in a reliable environmental adaptability with 115–205 mAh g −1 from −5 °C~70 °C at 0.1 A g −1 . Furthermore, when applied to potassium-ion hybrid capacitors with active carbon as cathode, PNTCDA@900 delivers a reversible capacity of 53.5 mAh g −1 after 800 cycles at 2 A g −1 . The current work will be significant for the development of potassium-ion storage.