Development of P3-K0.69CrO2 as an ultra-high-performance cathode material for K-ion batteries. Issue 10 (23rd July 2018)

• Record Type: Journal Article
• Authors: Hwang, Jang-Yeon; Kim, Jongsoon; Yu, Tae-Yeon; Myung, Seung-Taek; Sun, Yang-Kook
• Is Part Of: Energy & environmental science. Volume 11:Issue 10(2018)
• Page Start: 2821
• Page End: 2827
• Publication Date: 2018-07-23
• Subjects: Energy conversion -- Periodicals; Fuel switching -- Periodicals; Environmental sciences -- Periodicals; Environmental chemistry -- Periodicals; 333.79
• DOI: 10.1039/c8ee01365a
• Languages: English
• ISSNs: 1754-5692

Abstract

Abstract : P3-K0.69 CrO2 cathode is successfully synthesized via an electrochemical ion-exchange route and delivers excellent cycling stability and power capability in K-ion batteries. Abstract : Potassium-ion batteries (KIBs) are emerging as a promising energy storage technology because of their low cost and high energy density. However, the large size of K + ions hinders the reversible electrochemical potassium (de)insertion in the host structure, limiting the selection of suitable electrode materials for KIBs. Herein, we designed and exploited a new layered oxide, P3-type K0.69 CrO2 (hereafter denoted as P3-K0.69 CrO2 ), as a high-performance cathode for KIBs for the first time. The proposed P3-K0.69 CrO2 cathode was successfully synthesized via an electrochemical ion-exchange route and exhibited the best cycling performance for a KIB cathode material to date. A combination of electrochemical profiles, ex situ X-ray diffraction, and first-principles calculations was used to understand the overall potassium storage mechanism of P3-K0.69 CrO2 . Based on a reversible phase transition, P3-K0.69 CrO2 delivers a high discharge capacity of 100 mA h g −1 and exhibits extremely high cycling stability with ∼65% retention over 1000 cycles at a 1C rate. Moreover, the K-ion hopping into the P3-K0.69 CrO2 structure was extremely rapid, resulting in great power capability of up to a 10C rate with a capacity retention of ∼65% ( vs. the capacity at 0.1C).