Wide-voltage-window amphiphilic supramolecule excluded-volume electrolytes for ultra-durable full-cell aqueous potassium-Ion batteries

Aqueous potassium-ion batteries (AKIBs) are promising candidates for large-scale energy storage. However, the performance of AKIBs is restricted the dissolution of electrode materials and the narrow voltage window of aqueous electrolytes. Herein, we report the amphiphilic supramolecule modified aqueous K-ion electrolytes with synergistic functions of excluded-volume effect and hydrogen bond networks, which greatly reduce the activity of water molecules, inhibit the dissolution of active materials, and expand the operation voltage window (>3.4 V). Moreover, the as-assembled full-cell AKIBs exhibit an open-circuit voltage of 2.0 V, good rate capability, wide operating temperature range (−20 to 90 °C), and ultralong cycling life (with a capacity retention of 97.8 % after 10,000 cycles at 10 C). The study makes it possible for aqueous electrolytes to possess wide voltage window and temperature endurance, greatly expanding the choices of practicable electrolyte and paving the way of high-voltage aqueous batteries towards sustainable, safety and low-cost energy storage.