No abstract

High-quality sized FeFe(CN)6 delivered a reversible capacity of 124 mA h g−1 at the current rate of 0.5C for KIB, and still retained a reversible capacity of 93 mA h g−1 at 5C with a coulombic efficiency of 100%.

Exploring novel structure prototype and mineral phase, especially open framework material, is crucial to developing high-performance Na-ion battery cathodes in view of potentially faster intrinsic diffusion of Na + in lattices. Perovskite phases have been widely applied in solar cells, fuel cells, and electrocatalysis; however, they are rarely attempted as energy storage electrode materials. This study proposes pre-expanding perovskite iron fluoride (KFeF 3 ) framework by stuffing large-sized K + as a channel filler, which is advantageous over Na + , NH 4 + , and H 2 O molecule filler in terms of structure robustness, symmetry, and connectivity. K + stuffing leads to the preservation of a more "regular" cubic phase with fast isotropic 3D diffusion as a consequence of no distortion of FeF 6 octahedra during K-Na electrochemical exchange and following Na-insertion cycling. High-rate Na-storage is achievable with a reversible capacity of 110, 70, and 40 mAh g −1 at 0.1, 2, and 10 C, respectively, for this open framework fluoride cathode, benefiting from solid solution electrochemical behavior and high intrinsic diffusion coefficient. It is thought that this rate performance is currently the best among Na-storage fluoride materials.

Studies of transition metal dichalcogenides (TMDs) can be traced back to the 1970s but have been abandoned for a while due to the fire hazard of lithium metal batteries. Herein,...

A Prussian blue LiFeFe(CN) 6 thin-film cathode is fabricated by a nonvacuum coating technology without post-annealing process. The thin film of the solid electrolyte lithium phosphorus oxynitride (LiPON) is deposited onto the cathode by using radio-frequency magnetron sputtering. Then, the lithium metal anode is deposited on the LiPON film by the thermal evaporation method to fabricate the all-solid-state LiFeFe(CN) 6 /LiPON/Li battery with a thickness of 16 μm and a size of ∼10 cm 2 . Electrochemical properties of LiFeFe(CN) 6 /LiPON/Li battery are first investigated at various temperatures from −30 to 80 °C. Our results demonstrated that the all-solid-state LiFeFe(CN) 6 /LiPON/Li battery exhibits a discharge capacity of 82.5 mA h/g for the third cycle at 60 °C and shows stable cyclic performance within 200 cycles. These results provide the feasibility to assemble an all-solid-state lithium-ion battery by combining nonvacuum and vacuum techniques through an environmentally friendly process at low temperature.