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positive electrodes with 2,3-butanedione and with tetrabutyl ammonium bifluoride as model leaching agents. In the bifluoride trials, it was found that [Ni] in the leachate was proportional to X Co (X Ni ) 3 , where X M is the ideal stoichiometry in the bulk oxide, and inversely proportional to (X Mn ) 2 ; [Mn] to X Co (X Ni ); and [Co] to X Co . The relationships between metal concentrations and stoichiometry may indicate that nickel, as a next-nearest neighbor on the positive electrode surface, can make dissolution more favorable in some instances.

Twenty-four single-layer %32 mAh pouch cells are tested to determine the effect of electrode porosity on lithium plating. Twelve cells contain a graphite electrode that is 26% porous, and 47% for the other twelve. The cells are cycled using a 6-C charge and a C/2 discharge protocol at temperatures in the range of 20-50 C. A macro-homogeneous electrochemical model and microstructure analysis tool set are used to help interpret experimental observations for the effect of anode porosity and ambient temperature on fast-charging performance. Comparison between the two also highlights gaps in current theoretical understanding that need to be addressed. In post-test examination, lithium plating is seen in all cells, regardless of porosity. Elevated temperature is shown to reduce the amount of lithium plating and improve initial fast-charge capacity, but also changes the rate of other, less well-understood degradation mechanisms. Apparent kinetic rate laws, At þ Bt 1/2 , where A and B are constants, can be fit to most of the capacity loss and resistance increase data. The relative magnitudes of A and B change with temperature and porosity. The capacity loss data at 50 C from the high-porosity cells are fit by a logistics rate law.

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The effect of boric acid, sodium nitrate, and sodium dodecyl sulfate (SDS) on hydrogen permeation behaviors during the nickel electroplating was investigated using Devanathan–Stachurski method. The results demonstrated that the hydrogen permeation amount decreased with the increased addition of the H3BO3 and NaNO3 concentrations in the nickel electroplating bath. No decrease in the amount of hydrogen permeation was observed when SDS was used. Hydrogen permeation decreases in the presence of boric acid because it favors the formation of a more compact and less faulty Ni plating, improving the barrier effect caused by the nickel coating. In the case of NaNO3, it reacts with hydrogen ions (H+), diminishing them and hence hydrogen permeation. The three additives together showed a combined behavior and a very significant decrease of hydrogen permeation.