Yolk–Shell P3-Type K 0.5 [Mn 0.85 Ni 0.1 Co 0.05 ]O 2 : A Low-Cost Cathode for Potassium-Ion Batteries

[摘要] 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 K 0.5 [Mn 0.85 Ni 0.1 Co 0.05 ]O 2 (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.

[关键词] cathode materials;K0.5[Mn0.85Ni0.1Co0.05]O2;strain release;volume expansion;yolk–shell structure