Nanostructured Octahedral MnF2 as Anode Material for constructing Ultra-High Power Li-ion Hybrid Capacitors

Nanosizing materials is an effective approach to increase the contact area between the material and electrolyte, resulting in high specific capacity due to the availability of more active sites. In this study, well-formed nano-MnF2 was synthesized using a safe fluorine source through a one-step solvent thermal method. The specific capacity of nano-MnF2 as an anode material was 624.8 mAh g-1 after 200 cycles at 0.1A g-1, and it could reach up to 67.6 mAh g-1 after 6000 cycles at 2A g-1. Meanwhile, the use of ex-situ measurements confirmed that the capacity growth of MnF2 in cycling is mainly due to its valence change. Additionally, lithium-ion hybrid ca-pacitors (LIHCs) assembled using high-performance Mn-150 as the anode material and coconut shell biomass-derived carbon (CSBC) as the cathode material exhibited high specific capacitance (66.9F g-1 at 0.05A g-1), greater energy density (163.8Wh kg-1 at 105W kg-1), and higher power density (63000W kg-1 at 20.9Wh kg-1). The successful assembly of Mn-150//CSBC LIHCs and their ultra-high-power density demonstrate the great potential of MnF2 anode materials in LIHCs, providing new insights for future development of anode materials for LIHCs.