Layered P2‐Type K0.44Ni0.22Mn0.78O2 as a High‐Performance Cathode for Potassium‐Ion Batteries. (3rd October 2019)

• Record Type: Journal Article
• Authors: Zhang, Xinyuan; Yang, Yubo; Qu, Xianlin; Wei, Zhixuan; Sun, Ge; Zheng, Kun; Yu, Haijun; Du, Fei
• Is Part Of: Advanced functional materials. Volume 29:Number 49(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-10-03
• Subjects: full cells -- Ni/Mn‐based layered oxides -- potassium‐ion batteries -- stable CEI layers; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201905679
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Potassium‐ion batteries (KIBs) are emerging as one of the most promising candidates for large‐scale energy storage owing to the natural abundance of the materials required for their fabrication and the fact that their intercalation mechanism is identical to that of lithium‐ion batteries. However, the larger ionic radius of K + is likely to induce larger volume expansion and sluggish kinetics, resulting in low specific capacity and unsatisfactory cycle stability. A new Ni/Mn‐based layered oxide, P2‐type K0.44 Ni0.22 Mn0.78 O2, is designed and synthesized. A cathode designed using this material delivers a high specific capacity of 125.5 mAh g −1 at 10 mA g −1, good cycle stability with capacity retention of 67% over 500 cycles and fast kinetic properties. In situ X‐ray diffraction recorded for the initial two cycles reveals single solid‐solution processes under P2‐type framework with small volume change of 1.5%. Moreover, a cathode electrolyte interphase layer is observed on the surface of the electrode after cycling with possible components of K2 CO3, RCO2 K, KOR, KF, etc. A full cell using K0.44 Ni0.22 Mn0.78 O2 as the cathode and soft carbon as the anode also exhibits exceptional performance, with capacity retention of 90% over 500 cycles as well as superior rate performance. These findings suggest P2‐K0.44 Ni0.22 Mn0.78 O2 is a promising candidate as a high‐performance cathode for KIBs. Abstract : P2‐K0.44 Ni0.22 Mn0.78 O2 is introduced as a high‐performance cathode material for KIBs. The cathode undergoes a solid‐solution process during K + reversible insertion/extraction with a small volume change of 1.5%, beneficial to stability. Furthermore, a uniform and stable cathode electrolyte interphase film is formed on its surface.