Large interspaced layered potassium niobate nanosheet arrays as an ultrastable anode for potassium ion capacitor

• Potassium-ion battery (KIB) is a promising technology for large-scale energy storage applications due to their low cost, theoretically high energy density and abundant resources. However, the development of KIBs is hindered by the sluggish K+ transport kinetics and the structural instability of the electrode materials during K+ intercalation/de-intercalation. In the present investigation, we have designed a potassium-ion capacitor (KIC) using layered potassium niobate (K4Nb6O17, KNO) nanosheet arrays as anode and orange-peel derived activated carbons (OPAC) as fast capacitive cathode materials. The systematic electrochemical analysis with the ex-situ characterizations demonstrates that KNO-anode exhibits highly stable layered structure with excellent reversibility during K+ insertion/de-insertion. After optimization, the fabricated KNO//OPAC delivers both a high energy density of 116 Wh/kg and high power density of 10,808 W/kg, which is significantly higher than other similar hybrid devices. The cell also displays long term cycling stability over 5000 cycles, with 87 % of capacity retention. This study highlights the utilization of layered nanosheet arrays of niobates to achieve superior K-storage for KICs, paving the way towards the development of high-performance anodes for post lithium-ion batteries. © 2020

Nyckelord

Energy density

Potassium ion capacitor

Potassium Niobate

Waste derived carbon

Cathodes

Energy storage

Ions

Lithium-ion batteries

Nanosheets

Niobium compounds

Potassium

Abundant resources

Capacity retention

Electrochemical analysis

Energy storage applications

High energy densities

High power density

High-performance anodes

Structural instability

Anodes

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)