An exemplary embodiment relates to a medical device that includes a
rechargeable lithium-ion battery for providing power to the medical
device. The lithium-ion battery includes a positive electrode comprising
a current collector, a first active material, and a second active
material. The lithium-ion battery also includes a negative electrode
comprising a current collector and a third active material, the third
active material comprising a titanate material. The first active
material, second active material, and third active materials are
configured to allow doping and undoping of lithium ions. The second
active material exhibits charging and discharging capacity below a
corrosion potential of the current collector of the negative electrode
and above a decomposition potential of the first active material.