A high-performance cathode for potassium-ion batteries based on uniform P3-type K0.5Mn0.8Co0.1Ni0.1O2 porous microcuboids

Layered transition-metal oxides have engendered intensive attention as advanced cathode materials of potassium-ion batteries (PIBs). Nevertheless, their practical application to PIBs is hindered by the unsatisfactory cycling stability and rate capability. Herein, we successfully prepare uniform P3-type K0.5Mn0.8Co0.1Ni0.1O2 porous microcuboids (c-KMCNO) through a low-cost ethanol mediated coprecipitation strategy. The unique porous microcuboid structure considerably reduces the K+ diffusion distance and relieves internal strain caused by continuous K+ intercalation/deintercalation, thus improving the reaction kinetics and architectural integrity to boost the cycle stability and rate performance of c-KMCNO. As a cathode material for PIBs, c-KMCNO delivers a high reversible capacity of 94.5 mAh g−1 at 20 mA g−1, excellent rate capability of 49.5 mAh g−1 at 500 mA g−1, and remarkable cycling stability with a well-retained morphology at 100 mA g−1 after 300 cycles. Furthermore, a K-ion full cell of c-KMCNO//soft carbon demonstrates a reversible capacity of 54.3 mAh g−1 at 100 mA g−1 with a decent capacity retention of 81.1% over 100 cycles. Therefore, this porous microcuboid material demonstrates potential applications as high-performance low-cost cathode materials for PIBs.