Realizing Low‐Temperature Graphite‐based Rechargeable Potassium‐Ion Full Battery

Abstract Graphite (Gr) has been considered as the most promising anode material for potassium‐ion batteries (PIBs) commercialization due to its high theoretical specific capacity and low cost. However, Gr‐based PIBs remain unfeasible at low temperature (LT), suffering from either poor kinetics based on conventional carbonate electrolytes or K + ‐solvent co‐intercalation issue based on typical ether electrolytes. Herein, a high‐performance Gr‐based LT rechargeable PIB is realized for the first time by electrolyte chemistry. Applying unidentate‐ether‐based molecule as the solvent dramatically weakens the K + ‐solvent interactions and lowers corresponding K + de‐solvation kinetic barrier. Meanwhile, introduction of steric hindrance suppresses co‐intercalation of K + ‐solvent into Gr, greatly elevating operating voltage and cyclability of the full battery. Consequently, the as‐prepared Gr||prepotassiated 3,4,9,10‐perylene‐tetracarboxylicacid‐dianhydride (KPTCDA) full PIB can reversibly charge/discharge between −30 and 45 °C with a considerable energy density up to 197 Wh kg cathode −1 at −20 °C, hopefully facilitating the development of LT PIBs.

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