How do batteries work?

How do batteries really work? A convincing simple yet quantitative answer to this question has remained elusive. Textbooks and on-line sources have provided only descriptions but not explanations of basic electrochemistry. All calculations in electrochemistry are based on measured voltages, not atomic or molecular properties. Made-up explanations of batteries in terms of different “electron affinities” of different metals are widely believed but easily disproved, e.g. by concentration cells using the same metal for both electrodes.

A paper in the Journal of Chemical Education by Klaus Schmidt-Rohr (Chemistry) explains how batteries store and release energy, in quite simple terms but based on quantitative data. In the classical Zn/Cu galvanic cell, it is the difference in the lattice cohesive energies of Zn and Cu metals, without and with d-electron bonding, respectively, that is released as electrical energy. Zinc is also the high-energy material in a 1.5-V alkaline household battery. In the lead–acid car battery, intriguingly the energy is stored in split water (two protons and an oxide ion). Atom transfer into or out of bulk metals or molecules plays as big a role as electron transfer in driving the processes in batteries.

How Batteries Store and Release Energy: Explaining Basic Electrochemistry, Klaus Schmidt-Rohr, Journal of Chemical Education, 2018, 95 (10), pp 1801–1810.

Protected by Akismet
Blog with WordPress

Welcome Guest | Login (Brandeis Members Only)