摘要
Aqueous rechargeable batteries are cost-effective,easy to fabricate,and safe,deliver high energy output,and employ stable water-based electrolytes compared to organicbased lithium-ion batteries(LIBs).Aqueous Zn electrochemistry,specifically,has attracted researchers since the 1830s.Metallic Zn is a nearly ideal anode owing to its low cost(ca.2 USD kg^(−1)),existing supply chain,environmental benignity,relative safety,and high stability in water[−0.76 V vs standard hydrogen electrode(SHE)],as compared to Li.^(1−3) The high theoretical capacity(2e−@820 mAh g^(−1))and low polarizability(6×10^(−8)Ωm)further motivate Zn-based battery development,especially for stationary storage.2,4 Alkaline Zn batteries(AZBs)and neutral/mildly acidic Znion batteries(MZIBs)are proposed as rivals to the established Pb-acid and LIBs owing to their competitive theoretical energy densities(∼200−400 Wh L^(−1)).The efficiency of these inexpensive and safe battery technologies is dependent on the cathode type,Zn anode formulation,separator materials,and the electrolyte type(liquid,gel,solid state)and pH.While AZBs and MZIBs have commonalities,including Zn dendrite formation at high capacity utilization and inherent low voltage(Zn battery<3 V<LIB),unique materials chemistry challenges and operating principles distinguish them.For example,in AZBs,the preference is to prevent the crossover of the soluble anode oxidation product[zincate,Zn(OH)_(4)^(2−) anion]through the separator to the cathode,while MZIBs necessitate aversion to intermediate multiphase formation with active cathode material and removal of ambiguity in the reaction route of water-solvated Zn^(2+) cation with the cathode.
