Yolk–Shell P3‐Type K_0.5[Mn_0.85Ni_0.1Co_0.05]O₂: A Low‐Cost Cathode for Potassium‐Ion Batteries

Abstract

Low‐cost preparation methods for cathodes with high capacity and long cycle life are crucial for commercializing potassium‐ion batteries (PIBs). Presently, the charging/discharging strain that develops in the active cathode material of PIBs causes cracks in the particles, leading to a sharp capacity fade. Here, to abate the strain release and the need for an industrially relevant process, a simple low‐cost co‐precipitation method for synthesizing yolk–shell P3‐type K0.5[Mn0.85Ni0.1Co0.05]O2 (YS‐KMNC) was reported. As cathode material for PIBs, the YS‐KMNC delivers a high reversible capacity (96 mAh g–1 at 20 mA g–1) and excellent cycle stability (80.5% retention over 400 cycles at a high current density of 200 mA g–1). More importantly, a full battery assembled with the YS‐KMNC cathode and a commercial graphite anode exhibits a high operating voltage (0.5‐3.4 V) and an excellent cycling performance (84.2% retention for 100 cycles at 100 mA g–1). Considering the low‐cost, simple production process and high performance of YS‐KMNC cathode, this work could pave the way for the commercial development of PIBs.

Emerging of Heterostructure Materials in Energy Storage: A Review

“…[ 54 ] One typical structure is introduced void space in heterostructures, such as hollow structure, bowl‐like structure, and yolk‐shell structure. [ 55,56 ] The void space can mitigate the internal stress caused by violent volume expansion, leading to excellent cycling performance (Figure 5b). [ 57 ] Another typical structure is nicely arranged array structures formed by growing heterostructures on substrates, such as carbon cloth, nickel foam, nickel foil, and copper foil.…”

Challenges of layer-structured cathodes for sodium-ion batteries

“…These problems can be solved by adjusting the size of cathode materials and designing hollow micro/nano structures and special structures. 70,[84][85][86] The hollow micro/nano structure materials have high specific surface area and enough Na + storage sites. As a result, it can improve the rate performance and cycling stability of the cathode by effectively shortening the diffusion length of Na + , providing buffer for the volume strain generated in the cycling process, and enhancing the ionic conductivity.…”

“…These problems can be solved by adjusting the size of cathode materials and designing hollow micro/nano structures and special structures. 70,84–86…”

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

“…The 3D framework with uniform carbon coating provided rapid K-ion diffusion channels and a 3D electron transport network during K + extraction/insertion. Recently, Hao et al [162] designed a microscale yolk-shell P3-K 0.5 [Mn 0.85 Ni 0.1 Co 0.05 ]O 2 (YS-KMNC) cathode which delivered a discharge capacity of 96 mAh g −1 at 20 mA g −1 and showed excellent cyclability with 80.5% capacity retention over 400 cycles at 200 mA g −1 . Analysis of the strain variation during volume expansion of the cathode materials using finite element analysis (Figure 15c,d) revealed that the yolk-shell structured KMNC experienced lower internal stress than conventional KMNC.…”