对“化学电源”的学科理解

Disciplinary Analysis of “Chemical Power Source”

以《化学反应原理》教科书中的“化学电源”一节为素材,从热力学和动力学视角解释为何众多的自发化学反应不能制成实用的化学电源。将锌锰电池的电极电势分别与碱性溶液中溶剂水的氧化、还原电极电势比较,可知该电池的正极MnO_(2)属于热力学稳定,负极Zn属于动力学稳定(因为H_(2)在Zn上难以析出)。铅酸蓄电池的两电极都属于动力学稳定,正极PbO_(2)上析氧困难,负极Pb上析氢困难。

Based on the section“chemical power source”in the textbook Principles of Chemical Reactions,this paper explains why numerous spontaneous chemical reactions cannot be made into practical chemical power sources from the perspective of thermodynamics and kinetics.Comparing the electrode potential of zinc-manganese battery with the oxidation and reduction electrode potential of solvent water in alkaline solution,it is concluded that the positive electrode MnO_(2) of the battery is thermodynamically stable and the negative electrode Zn is kinetically stable,because H_(2) is difficult to precipitate on Zn.Both electrodes of lead-acid storage battery are kinetically stable,oxygen evolution on positive electrode PbO_(2) is difficult while hydrogen evolution on negative electrode Pb is difficult.