The discharge behavior of thermogalvanic cells based on a dissolved redox couple, namely ferro‐ferricyanide, was investigated as a function of redox couple concentration, temperature difference, electrode placement and configuration, and forced convection. The principal source of cell polarization was found to be the rate of mass transfer of electroactive species to the electrode surfaces. This concentration polarization is instrumental in limiting the power output of aqueous redox thermogalvanic cells to values <0.1 mW cm−2. A practical feature of such cells, however, is that a continuous power output can be maintained indefinitely provided that the half‐cell temperature difference remains constant.

A preliminary evaluation was made of the cathodic discharge of nickel sulfides in LiC104-propylene carbonate electrolyte. Theoretical energy densities of approximately 400-700 whr/lb are calculated, depending on the choice of the specific nickel sulfide. The nickel sulfides tested had solubilities ~10-4M in the charged and partially discharged state. High coulombic efficiencies (>50%) were achieved at 1 ma/cm ~. A discharge of 10 ma/cm'-' could be sustained, but at a lower efficiency. The discharge plateau is between 1.8 and 1.4v.

The electrochemical behavior of trace quantities of water (1–30 mM) in LiClO4‐normalpropylene carbonate solutions was studied via chronopotentiometric and cyclic voltammetric techniques. It was observed that, with platinum electrodes, the chronopotentiometric constant increased with increasing current density up to a constant limiting value at high current densities. Analysis of the cyclic voltammetric results showed analogous behavior. The reaction product of H2O reduction was inferred to be a porous, insoluble film of normalLiOH . This layer apparently acts to block part of the electrode surface thereby increasing the effective current density, decreasing Τ and hence iΤ½ . From the concentration dependence of iΤ½ and of ip/v½ it was further inferred that strong complexes were formed between water and Li+ ion which decreased the activity coefficient of H2O . Current reversal subsequent to the reduction step showed an oxidation step which may be associated with an adsorbed film of atomic hydrogen on the platinum surface.

not Available.

The potential distribution in thin electrodes of the automotive battery type was determined experimentally and predicted from a model. Potentials at various locations on the plates were measured in cells at various discharge rates and for different plate widths. A model, based on the application of Kirchoff's law to each intersection of grid members, was solved numerically to predict potential distribution. The measured and calculated potential distributions were in excellent agreement. The implications of the model are discussed with emphasis on the interaction between grid design, grid weight, and plate performance. Performance is measured in terms of the maximum (i.e., the tab‐to‐corner) ohmic potential loss.