3D Macroporous Engineering of Metal Sulfide-Based Materials for High-Capacity and Ultrastable Potassium Storage under Room and Extreme Temperatures

K-ion batteries (KIBs) with abundant resources are being extensively pursued, but high-capacity anode materials for storing the larger-sized K ions suffer from electrochemical instability. This instability worsens at elevated temperatures, as increasing the temperature would exacerbate the chemical and mechanical instability of the electrode and its interface with the electrolytes, making the pursuit of stable high-capacity anode materials for high-temperature KIBs a formidable challenge. Herein, we demonstrated that low-crystallinity zinc sulfide (ZnS) embedded in a three-dimensional macroporous carbon skeleton (3D-M-ZnS) could act as a high-performance anode for room- and high-temperature KIBs. The well-dispersed low-crystallinity ZnS can deliver superior electrochemical activity; the 3D macroporous architecture with hollow building blocks can facilitate the K⁺ transport and alleviate volume deformation, thus achieving high capacity (400 mAh g^-1) and ultrastable cyclability with ∼100% retention of initial capacity for 5600 cycles at room temperature (RT). Even at an extreme temperature of 60 °C, this 3D-M-ZnS composite still promised an outstanding cyclability (no capacity fading over 430 cycles at 2A g^-1) with a high reversible capacity (447 mAh g^-1 at 30 mA g^-1) and a superior rate, which is a much better comprehensive battery performance than that of the existing high-temperature KIBs anodes. This contribution opened an effective avenue in building reliable anodes for high-performance K-ion storage, even under extreme temperatures.