Fabricating low-temperature-tolerant and durable Zn-ion capacitors via modulation of co-solvent molecular interaction and cation solvation

基于共溶剂分子间相互作用和阳离子溶剂化的耐低温、长寿命锌离子电容器(英文)

Aqueous Zn-based energy-storage devices have aroused much interest in recent years.However,uncontrollable dendrite growth in the Zn anode significantly limits their cycle life.Moreover,the poor low-temperature performance arising from the freezing of aqueous electrolytes at sub-zero temperatures restricts their practical applications in cold regions.Here,we fabricated low-temperature-tolerant and durable Zn-ion hybrid supercapacitors(ZHSCs)via modulating a co-solvent water/ethylene glycol electrolyte.The interaction of intermolecular hydrogen bonds between water and ethylene glycol as well as cation solvation was systematically investigated by tuning the co-solvent composition.The results illustrate that the ZnSO_(4)/water/ethylene glycol(65%)electrolyte possesses high ionic conductivity at low temperatures and effectively prevents the dendrite formation of the Zn anode.The as-fabricated ZHSCs exhibit long-term cyclability and are capable of working at sub-zero temperatures as low as -40℃.The present ZHSCs are anti-freezing and cost-effective,which may find new applications in the fields of next-generation electrochemical energy storage devices.

近年来,水系锌基储能器件引起了人们极大的关注.然而,锌负极中不可控的枝晶生长限制了其循环寿命.另外,水系电解液在零度以下冻结导致较差的低温性能,限制了其在寒冷地区的实际应用.以锌离子混合电容器为例,本文报道了通过调节水/乙二醇共溶剂电解液来构建耐低温、长寿命的锌离子混合电容器.通过调控共溶剂的组分,系统探索了水和乙二醇分子间的氢键作用以及阳离子溶剂化对电化学性能的影响.结果表明,硫酸锌/水/乙二醇(65%)电解液在低温下具备较高的离子电导率,并且可以有效地防止锌负极中枝晶的形成.组装的锌离子混合电容器具有长循环稳定性,能够在零下40℃的极端低温条件下工作.该锌离子混合电容器成本低,具有较好的抗冻特性,有望应用于下一代电化学储能领域.