Strengthening Aqueous Electrolytes without Strengthening Water
Strengthening Aqueous Electrolytes without Strengthening Water
复制标题
强化水电解质而不强化水
DOI：
10.1002/anie.202307212
复制
发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Stylianou, Kyriakos C.
中科院分区：
文献类型：
--
作者：
Tang, Longteng;Xu, Yunkai;Zhang, Weiyi;Sui, Yiming;Scida, Alexis;Tachibana, Sean R.;Garaga, Mounesha;Sandstrom, Sean K.;Chiu, Nan‐Chieh;Stylianou, Kyriakos C.
水性电解质通常具有较差的电化学稳定性；然而，共晶水溶液- 25wt。% LiCl和62 wt。% h3po4冷却至- 78℃时，稳定性窗口明显变宽。综合实验和模拟结果表明，冷却后，Li+离子的水化程度降低并与Cl−配对，形成冰状水团簇，H⋅⋅⋅Cl−键增强。令人惊讶的是，这种低温溶剂化结构并没有加强水分子的O - H键，这与传统观点相反，即提高水的稳定性需要加强O - H共价键。我们提出了水在电解质中的低温惰性的更普遍的机制：氢氧析出反应的副产物OH -和H+的不有利溶剂化。为了证明这种稳定性，我们展示了一种使用limn2o4阴极和CuSe阳极的水锂离子电池，其能量密度高达109 Wh/kg。这些结果突出了水电池在极地和地外任务中的潜力。
Aqueous electrolytes typically suffer from poor electrochemical stability; however, eutectic aqueous solutions—25 wt.% LiCl and 62 wt.% H3PO4—cooled to −78 °C exhibit a significantly widened stability window. Integrated experimental and simulation results reveal that, upon cooling, Li+ions become less hydrated and pair up with Cl−, ice‐like water clusters form, and H⋅⋅⋅Cl−bonding strengthens. Surprisingly, this low‐temperature solvation structure does not strengthen water molecules’ O−H bond, bucking the conventional wisdom that increasing water's stability requires stiffening the O−H covalent bond. We propose a more general mechanism for water's low temperature inertness in the electrolyte: less favorable solvation of OH−and H+, the byproducts of hydrogen and oxygen evolution reactions. To showcase this stability, we demonstrate an aqueous Li‐ion battery using LiMn2O4cathode and CuSe anode with a high energy density of 109 Wh/kg. These results highlight the potential of aqueous batteries for polar and extraterrestrial missions.