K⁺ modulated K⁺/vacancy disordered layered oxide for high-rate and high-capacity potassium-ion batteries

Abstract

With high theoretical capacity and applicable operating voltage, layered transition metal oxides are potential cathode for potassium-ion batteries (PIBs). However, K+/vacancy ordered structure in these oxides limits the K+ transport...

Recent Progress and Prospects of Layered Cathode Materials for Potassium‐ion Batteries

“…Reproduced with permission. [ 48 ] Copyright 2020, The Royal Society of Chemistry. Polyhedral view of the crystal structure of P2‐K 2 Ni 2 TeO 6 along g) the c ‐axis and h) ab plane.…”

“…Recently, Xiao et al reported the positive effects of K + /vacancy disordered in layered oxide K 0.7 Mn 0.7 Ni 0.3 O 2 , which exhibits higher discharge voltage, capacity, rate capability, and cycling stability than the K + /vacancy ordered phase (K 0.4 Mn 0.7 Ni 0.3 O 2 ), as shown in Figure 5 d‐f. [ 48 ] The strong K + –K + electrostatic repulsion by increasing the K + content reduces the energy difference of the K + sites, thus breaking the K + /vacancy ordered structure. In addition, the doped transition metal in layered oxides with compatible ionic radius but quite different Fermi levels suppress the M n+ charge ordering, resulting in the K + /vacancy disordering.…”

“…f) Cycling performance of K 0.7 Mn 0.7 Ni 0.3 O 2 and K 0.4 Mn 0.7 Ni 0.3 O 2 . Reproduced with permission [48]. Copyright 2020, The Royal Society of Chemistry.…”

High‐Voltage Potassium Ion Micro‐Supercapacitors with Extraordinary Volumetric Energy Density for Wearable Pressure Sensor System

“…In contrast, substantial efforts have been devoted into potassium ion energy storage devices, owing to the abundant potassium resource in crust and comparable energy density. [ 24–26 ] The reduction potential of potassium (−2.93 V vs SHE) gets close to that of lithium (−3.04 V vs SHE), enabling a high operating voltage of potassium ion batteries comparable to lithium ion batteries. [ 27,28 ] Moreover, potassium ions in non‐aqueous electrolyte have a weaker solvation effect and smaller Stokes’ radius than lithium ions, contributing to a higher ion transfer number and conductivity.…”

“…[21][22][23] In contrast, substantial efforts have been devoted into potassium ion energy storage devices, owing to the abundant potassium resource in crust and comparable energy density. [24][25][26] The reduction potential of potassium (−2.93 V vs SHE) gets close to that of lithium (−3.04 V vs SHE), enabling a high operating voltage of potassium ion batteries comparable to lithium ion batteries. [27,28] To cate for the rapid development of flexible, wearable and implantable microelectronics, the miniaturized and integrated energy storage devices with mechanically robust properties, high voltage, and highly compatible integration are in extreme demand.…”