Enhanced K ⁺ ‐Solvent Co‐Intercalation Into Regenerated Spent Graphite a High‐Rate Capable Anode for Potassium‐Ion Batteries at Different Temperatures

ABSTRACT Globally accelerating the requirement for ecologically sound and economically efficient energy storage prompted interest in battery technologies. Since the origin, lithium‐ion batteries (LIB) dominated with high energy density and mature infrastructure; however, given the scarcity of lithium resources and rising cost, there has been a driving force to explore alternatives like sodium‐ion battery and potassium‐ion battery technologies. Among these, KIBs offer high power density, favorable K + ion diffusion kinetics, wider range of voltage at higher potential, eliminates the formation of intermetallic compounds, is abundant and also cost‐effective, unlike LIBs. KIBs can use industrial standard graphite as anode unlike NIBs but both behave similarly during ion‐solvent co‐intercalation. Eventually reached with versatile electrode, graphite, as anode exhibits reversible potassium intercalation and charge storage mechanism with structural constraints of larger potassium‐ions and lacks stability. Herein, we introduced graphite anodes recycled from spent LIBs, regenerated as anodes for KIBs‐propounding a circular economy. The optimized sample tested with an ether‐based electrolyte exhibited 107 mAh/g capacity at 5 A/g and was stable for 1000 cycles at room temperature. This sustainable material suitably tailored, exhibits good electrochemical performance at both room and low temperatures. Also, the kinetics of co‐intercalation mechanism was investigated using electrochemical impedance spectroscopy, ex situ x‐ray diffraction and transmission electron microscopy. To a greater extent, the work highlights the positive outcomes of usage of spent graphite in advanced resource‐efficient energy storage solutions. This idea keeps away resource exploitation, environmental contaminations and economic imbalances, reinforcing a sustainable circular economy.