Coulometric determination of metal carbonates in battery electrodes by destructive analysis

A gravimetric method of destructive analysis of silver-zinc and nickel-cadmium battery electrodes to determine carbonate composition has been standard practice for fifteen years. This method is tedious, requires large sample sizes, and lacks both accuracy and precision. An alternative coulometric method to determine carbonate compositions using an off-the-shelf commercial instrument was investigated and found to be superior. The coulometric instrument requires half the time, one-tenth the amount of sample, and is far more accurate and precise. The instrument also promises to be used in conjunction with thermogravimetric analysis for simultaneous analysis of silver-oxides and silver-carbonates. This paper compares the gravimetric and coulometric methods and illustrates the greater accuracy obtainable with the new method in the analysis of silver-oxide electrodes