  We investigate a solid-state, reversible, alkali-ion battery (AIB) capable of
regulating the density of alkali atoms in a vacuum system used for the
production of laser-cooled atoms. The cold-atom sample can be used with
in-vacuum chronoamperometry as a diagnostic for the voltage-controlled
electrochemical reaction that sources or sinks alkali atoms into the vapor. In
a combined reaction-diffusion-limited regime, we show that the number of
laser-cooled atoms in a magneto-optical trap can be increased both by initially
loading the AIB from the vapor for longer, and by using higher voltages across
the AIB when atoms are subsequently sourced back into the vapor. The time
constants associated with the change in atom number in response to a change in
AIB voltage are in the range of 0.5 s - 40 s. The AIB alkali reservoir is
demonstrated to survive oxidization during atmospheric exposure, simplifying
reservoir loading prior to vacuum implementation as a replacement for
traditional resistively-heated dispensers. The AIB capabilities may provide an
improved atom number stability in next-generation atomic clocks and sensors,
while also facilitating fast loading and increased interrogation times.
