Aqueous supercapacitors (SCs) have received considerable attention owing to the utilization of low-cost, non-flammable, and low-toxicity aqueous electrolytes thus could eliminate the safety and cost concerns, but their wide temperature range applications have generally suffered from frozen of electrolyte and insufficient ionic conductivity at low temperatures. Herein, we demonstrate the feasibility of using an unconventional Deep Eutectic Solvent (DES) based on H₂O-Mg(ClO₄)₂·6H₂O binary system as electrolyte to construct all-climate aqueous carbon-based SC. This unconventional class DES completely base on inorganic substances and achieving simply mix inexpensive salts and water together at the right proportions. Attributed to the attractive feature of extremely low freeze temperature of −69 °C, this electrolyte can enable the 1.8 V carbon-based SC to fully work at −40 °C with outstanding cycling stability. This DES electrolyte comprising of a single salt and a single solvent without any additive will open up an avenue for developing simple and green electrolytes to construct all-climate SC.

水性超级电容器（SCs）由于使用低成本，不易燃且低毒性的水性电解质而受到了广泛的关注，因此可以消除安全性和成本问题，但是它们在宽温度范围内的应用通常会遇到电解质冻结的问题低温下离子电导率不足。在此，我们证明了使用基于H ₂ O-Mg（ClO ₄）₂ ·6H ₂的非常规深共晶溶剂（DES）的可行性以二元体系为电解质，构建全气候水性碳基SC。这种非常规的DES类别完全基于无机物质，并且可以简单地以适当的比例将廉价的盐和水混合在一起。归因于极低的-69°C的冷冻温度，该电解液具有出色的吸引力，可使1.8 V碳基SC在-40°C的温度下完全工作，并具有出色的循环稳定性。这种由单一盐和单一溶剂组成而不含任何添加剂的DES电解质将为开发简单绿色的电解质以构建全气候SC开辟一条道路。