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.