Intercalation pseudocapacitance of hollow carbon bubbles with multilayered shells for boosting K-ion storage

Abstract

The upsurge of potassium-ion energy storage devices promotes the fast development of K-ion storage electrode materials, but the poor kinetics and low capacity resulted from the large size of K-ions need more sophisticated structural design and mechanism innovations for exploring high-performance anode materials. In this study, we reported a novel carbon skeleton constructed by hollow carbon bubbles with a unique multilayered shell and an impressive large interlayer spacing of 0.76 nm. This unique ordered carbon layered structure with much enlarged interlayered distance makes it meet the strict demand for inducing intercalation pseudocapacitance, leading to a state of the art K-ion storage capacity at a high rate of 274 mA h g⁻¹ at 10 A g⁻¹. As a proof of application, the resultant high-capacity carbon is incorporated into a potassium ion capacitor, showing an ultrahigh energy density of 152 W h kg⁻¹ and an excellent cycling capability of only 0.0026% fading per cycle at 2 A g⁻¹. Therefore, our study not only expands the family of intercalation pseudocapacitance, but also paves a new way to explore new materials for high performance K-ion storage devices.