Many portable and implantable medical devices, such as pacemakers and insulin pumps depend on batteries. Current battery technologies struggle to provide long-lasting power, requiring frequent replacements or recharging, which can be inconvenient or even risky for patients. 

As medical devices become smaller and more compact, they require components that are both energy-efficient and powerful. Achieving this balance is challenging, as miniaturization often leads to higher energy consumption relative to size. 

In clinical environments, medical devices must operate reliably even in the event of power outages or fluctuations. Ensuring an uninterrupted power supply for critical devices like ventilators or defibrillators is a major concern, particularly in settings with unstable power grids or during emergencies.