Recent Advances in Layered Metal‐Oxide Cathodes for Application in Potassium‐Ion Batteries

Abstract

To meet future energy demands, currently, dominant lithium‐ion batteries (LIBs) must be supported by abundant and cost‐effective alternative battery materials. Potassium‐ion batteries (KIBs) are promising alternatives to LIBs because KIB materials are abundant and because KIBs exhibit intercalation chemistry like LIBs and comparable energy densities. In pursuit of superior batteries, designing and developing highly efficient electrode materials are indispensable for meeting the requirements of large‐scale energy storage applications. Despite using graphite anodes in KIBs instead of in sodium‐ion batteries (NIBs), developing suitable KIB cathodes is extremely challenging and has attracted considerable research attention. Among the various cathode materials, layered metal oxides have attracted considerable interest owing to their tunable stoichiometry, high specific capacity, and structural stability. Therefore, the recent progress in layered metal‐oxide cathodes is comprehensively reviewed for application to KIBs and the fundamental material design, classification, phase transitions, preparation techniques, and corresponding electrochemical performance of KIBs are presented. Furthermore, the challenges and opportunities associated with developing layered oxide cathode materials are presented for practical application to KIBs.

Uniform P2-K0.6CoO2 Microcubes as a High-Energy Cathode Material for Potassium-Ion Batteries

“…Layered TM oxides are regarded as prospective materials for PIB cathodes because they can hopefully achieve both large volumetric and gravimetric energy densities. 27 The potassium-based layered TM oxides can be classified into two major categories: P2 and P3 types, where all potassium ions hold the prismatic sites in the space between the MO 2 slabs with the oxygen arraying as AB BA AB or AB BC CA along the c axis, respectively. 17 Despite that both P2 and P3 type oxides can exbibit high specific capacity, the cyclic stability is generally unsatisfactory because of the multiphases transition during depotassiation/ potassiation.…”

“…As the promising cathode materials, Prussian blue analogues, , polyanionic compounds, , and layered transition-metal (TM) oxides − have been extensively studied, while their entire potassium storage properties are still unsuitable for the large-scale application of PIBs. Layered TM oxides are regarded as prospective materials for PIB cathodes because they can hopefully achieve both large volumetric and gravimetric energy densities . The potassium-based layered TM oxides can be classified into two major categories: P2 and P3 types, where all potassium ions hold the prismatic sites in the space between the MO 2 slabs with the oxygen arraying as AB BA AB or AB BC CA along the c axis, respectively .…”

Enhanced Performance of KVPO4F0.5O0.5 in Potassium Batteries by Carbon Coating Interfaces

“…4 Various types of materials have been proposed at the positive electrode for KIBs. 5 Among them, we can mention Prussian blue analogues, 6−9 layered transition metal oxides, 10,11 and polyanionic compounds. 12−14 Phosphate-based polyanionic positive electrode materials such as potassium vanadium phosphate fluoride (KVPO 4 F) and potassium vanadium phosphate oxide (KVOPO 4 ) are among the best candidates due to their high theoretical energy density of 560 Wh kg −1 , which is similar to that of the commercial LiFePO 4 in LIBs, 15−18 and the robustness of their highly covalent framework (promoting high structural and thermal stability).…”

Exploring the electrochemical stability mechanism of a SnS2-based composite in dimethoxyethane electrolytes for potassium ion batteries

“…9–11 However, the conventional commercial graphite anode for LIB presents a deficient electrochemical performance in KIBs due to the large radius of the K-ion, which cannot meet the requirements of the KIB. 12–14 Therefore, developing a high-performance anode for K-ion storage becomes necessary.…”