A battery configured to support a relatively high rate of energy discharge relative to its capacity for energy intensive therapy delivery. The battery includes a feedthrough insulator cap disposed within the interior of the battery on at least a portion of a ferrule, at least a portion of an insulator, and at least a portion of a pin, which define a feedthrough extending through an enclosure of the battery; a first electrode disposed within the enclosure and electrically coupled to the pin; a second electrode disposed within the enclosure and separated a distance from the first electrode; and an electrolyte disposed between the first electrode and the second electrode. During operation of the battery, the feedthrough insulator cap reduces dendrite formation on at least a portion of the ferrule, the pin, or both.