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.