The host-guest effect of D-xylose constructs the weak-synergistic sheath structure of Zn2+ to achieve high performance of aqueous zinc ion batteries at the low temperature

Abstract

Aqueous zinc ion batteries (AZIBs) have been widely concerned because of their low cost and high safety. However, zinc anodes are affected by active H2O, which promotes side reactions, and performs poorly at low temperatures. Herein, a weak-synergistic solvated sheath structure of Zn2+ is implemented by constructing a host–guest solvation modulation effect with the addition of D-xylose. As the host, D-xylose can replace the guest H2O in the solvated shell of Zn2+, weaken the interaction of Zn2+ with the guest H2O and SO42−, and destroy the original hydrogen bond network of the guest H2O-H2O. This electrolyte can greatly reduce side reactions induced by reactive H2O and lower the freezing point. Consequently, the electrolyte containing D-xylose has a high ionic conductivity of 21.2 mS cm−1 at −10 °C. The Zn||Zn battery can run stably for more than 2000 h at 25 °C (1 mA cm−2) and −10 °C (0.5 mA cm−2). Furthermore, the Zn||PANI battery displays promising capacity and sustained stability over 1000 cycles at −10 °C with an average CE of up to 100 %. This study highlights a new electrochemical perspective to achieve a weak-synergistic structure around Zn2+, providing new insights into the application of AZIBs at low temperatures.