Initially proposed in 1868 by Georges Leclanché, the Zn/MnO2 battery concept has undergone numerous modifications and constant improvements up to the present day, when the latest developments are capable of delivering 130 Wh/kg (320 Wh/L). They are produced in tens of billions of units a year; Panasonic alone has announced that it will have produced 100 billion between 2000 and 2020. So we're not talking about obsolete systems here, but about very common items in our everyday environment.
Not only do these batteries use non-polluting, low-cost materials, but their simple design makes them easy to develop and recycle on a large scale. The history of the chemical evolution of these batteries is exemplary, as it has been punctuated by innovations and discoveries that perfectly illustrate the interconnections between i) the nature of the electrolyte (saline or alkaline), ii) safety of use, iii) minimization of self-discharge, iv) the texture of electrode materials, v) crystallochemistry, vi) temperature and mode of use (target applications), vii) material purity, viii) power output, etc.
To optimize the level of their exchanges and the speed of progress in their community, researchers involved in this field very early on standardized their test protocols and cell formats (AAA, C, D...). At the end of the 1960s, they also created a bank of reference MnO2 powders (International Battery Association) available in large quantities to all. This remarkable spirit is undoubtedly behind the great vitality and adaptability of this technological sector, as illustrated by the development of alkaline batteries in the late 1960s.
But there is still one last major challenge to be met : to make these Zn/MnO2 cells into Zn/MnO2 batteries, i.e. to make them reversible/rechargeable. This is currently the subject of a great deal of research worldwide, which is unfortunately anarchic and abundant. Let's hope that it would be reasonable to draw more inspiration from the spirit of previous progress, achieved through concerted investigations, essentially simple experiments and a high level of standardization.
