Have I made nickel oxyhydroxide somehow with potassium carbonate solution?

[realflow100]

I put a pair of pure nickel strips in a solution of potassium carbonate 34% by weight to water and  applied a current and voltage to them reversing the polarity a couple dozen times. 
and a dark black coating formed alternatingly on whichever electrode was the positive one. and the other electrode changed to a brighter nickel color.
Heres a picture of one of the strips of nickel. the dark part on the right is what was in the solution.
I also noted it has a voltage potential across it open circuit of about 1.23 to 1.38 volts.
if I replace one of the nickel strips with a zinc strip and charge the nickel strip as the positive with zinc as the negative it rests at about 1.8 to 1.83 volts pretty steady. and can light up a red LED for several minutes continously before it starts dimming significantly.
ive been experimenting for several months trying various solutions to try to make various kinds of rechargable diy batteries and thought this seemed to have potential or at the very least interesting

Edited January 10 by realflow100

[chenbeier]

Its an anodic oxidation to nickeloxides.

[realflow100]

but what kind of oxides? the dark oxide layer doesn't start to appear until the electrode is cycled repeatedly over and over many times with the polarity being reversed every time. and it does not show any green color. when its lighter it's slightly more brownish but when dark its just black.

and it also acts as a battery if paired with a suitable negative electrode like zinc graphite carbon iron or lead. I got over 1.4 amps of current briefly out of just a strip about  2.75 inches long and 8mm wide rolled up into a spiral with a thin separator to prevent shorts and was able to light up an LED for a good while.
it also holds a voltage identical to that of a nickel zinc battery if charged with a nickel and zinc electrode.

Edited January 12 by realflow100

[realflow100]

anyone have any ideas?