The Reduction of Manganese Dioxide in Leclanché‐Type Dry Cells as Displayed by Derivative Discharge Functions

Abstract

q ABSTRACTThe derivative discharge curves for ~-and 7-MnO2 down to ,~0.7V open cell voltage were resolved into one characteristic set of four normal distribution functions (peaks). Only peak positions shift to lower voltages for ~-compared to 7-MnO2. When the ratio of electrolyte to MnO2 is increased, the first peak increases while the other peaks decrease (the second passes through a maximum) and at a mass ratio above 14 only the first peak remains. The first peak represents direct reduction of Mn 4+ to soluble Mn e+ which ends at pH 7.5, the second is attributed to the formation of Mn(OH)~, and the third to the formation of MnOOH. Each reaction takes place throughout the depolarizer pellet before the next becomes significant. Electrochemical tests for the evaluation of the dry cell activity of MnO2 samples should be performed at the same mass ratio of electrolyte to MnO2 as used in commercial dry cells. Higher ratios lead to an overestimation of samples with Iow activity.

Peak Attribution of the Differential Capacity Profile of a LiCoO₂-based Three-electrode Li-ion Laminate Cell

“…The degradation of LIBs during charge/discharge operation has been investigated intensively in several studies through analysis of the differential capacity profile (dQ/dV vs. V). 4,[10][11][12][13][14][15] The differential capacity profile introduces a constant-current analytical method, wherein the behavior of the redox system is analyzed by monitoring the electrode potential resulting from the application of current. 10 Equation 1 shows that dQ/dV can be regarded as the current (I) divided by the sweep rate (dV/dt).…”

“…4,[10][11][12][13][14][15] The differential capacity profile introduces a constant-current analytical method, wherein the behavior of the redox system is analyzed by monitoring the electrode potential resulting from the application of current. 10 Equation 1 shows that dQ/dV can be regarded as the current (I) divided by the sweep rate (dV/dt).…”

Methods of non-destructive testing in studies of self-organization processes in protein films

“…Under the influence of electric field a conformational transformation occurs in the solution of a spiral single-stranded polynucleotide into a glomerulate one. The degree of transition is a linear function of the field strength [6].…”

Electrochemical Potential Spectroscopy: A New Electrochemical Measurement

“…The current pulse technique is another d-c technique that may provide complementary data to those obtained by the voltage stepping method. In this experiment a discharge is performed at constant current for a time and then the current is shut off (cell at open circuit) (8). When the cell is at open circuit, a chronopotentiogram is recorded to study cell kinetics and to extract nonequilibrium contributions to the cell voltage, principally the IR drop.…”

“…X T,P (Note that kr (electrochemical) is not a compressibility but is analogous to the compressibility.) Equation [8] shows that the incremental capacity, Ax/AV, is a response function for the electrochemical cell that is analogous to the isothermal compressibility times x. (Note that there is a sign ambiguity or possible confusion in the definition of Ax/AV.…”