MOF-5 as anodes for high-temperature potassium-ion batteries with ultrahigh stability

Among the families of modern energy storage devices, the potassium-ion batteries (PIBs) are emerging as a shining star with desired high energy density and interesting commercial application prospect. However, they still encounter the big question with intrinsically bad cycle stability, especially under high-temperature working conditions. In this work, we report the progress on exploring high-temperature PIBs with ultrahigh stability, based on metal organic framework-5 (MOF-5) as anode materials. At the fixed working temperature of 62.5 °C, the as-constructed PIBs have initial discharge and charge specific capacities of respective ∼ 1183 and 210 mA h g −1 at a current density of 200 mA g −1 , and hold a specific capacity of 160 mA h g −1 with a low decay of 0.15% per cycle over 150 cycles. Even at a high current density of 500 mA g −1 , they deliver a reversible specific capacity of 56 mA h g −1 with a tiny decay of 0.018% per cycle over 3000 cycles, which is the state-of-the-art one among those of high-temperature PIBs ever reported. The energy storage mechanism based on C O bond as the redox center is proposed.