Manganese fluoride as non-battery type anode for high performance Li-ion capacitors

Lithium-ion hybrid capacitors (LIHCs) are considered as promising next-generation energy storage devices with high energy density, large power density, and ultra-long cycle life. Anode material is an important factor affecting LIHCs. Here, we prepared hexagonal MnF2 with good morphology by solvothermal method. MnF2 was used as the anode to deliver a high specific capacity of 330 mAh g(-1) after 1050 cycles at 0.1 A g(-1). The specific capacity of MnF2 electrode, after 5000 cycles at 2 A g(-1), can also reach 65 mAh g(-1). LIHCs of MnF2 as anode and AC as cathode offer an excellent energy density of 81 Wh kg(-1) at 95 W kg(-1) and power density of 6840 W kg(-1) at 26 Wh kg(-1). Also, the capacity retention rate is 72% after 3000 cycles at 1 A g(-1). The implementation of MnF2//AC, an energy storage device, extends the practical application of MnF2 in energy storage.