Scalable Synthesis Nano-Perovskite K(MnNi)F Cathode by Homogeneous Precipitation Method for Potassium-Ion Batteries.

Potassium-ion batteries (KIBs) are favored by researchers because of the unique advantages. In this work, KIB cathode material nano-perovskite K(MnNi)F with concentration gradient was synthesized by EDTA-assisted homogeneous precipitation method for the first time and characterized. The solid solution material was deposited on the multi-walled carbon nanotubes (MWCNTs) to form K(MnNi)F/MWCNT nanocomposites to improve the electron conductivity of the electrode material so as to obtain the excellent electrochemical performance. As expected, the charge and discharge capacities of K(MnNi)F/MWCNTs after the 60th cycle can still reach 106.8 and 98.5 mAh g over the voltage range 4.2-1.2 V vs. K/K at the current density of 35 mA g, respectively. Electrochemical performance studies showed that solid solution K(MnNi)F had the potential applications as the cathode material for KIBs. Electrochemical impedance spectroscopy (EIS) was used to study the transport and reaction processes of ions at the solid-liquid interface. The main factors affecting electrochemical performance could be analyzed from the Nyquist plot of the EIS test.