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

•A novel K+ storage mechanism based on CO bond with six CO bonds as the redox centers is proposed.•Ultrahigh stability of PIBs under room temperature.•Ultrahigh stability of PIBs under high temperature. 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 CO bond as the redox center is proposed.