The continuously advancing technology of portable electronic devices requires more flexible batteries to power them. Batteries power a wide range of electronic devices including phones, laptop computers and medical devices such as cardiac pacemakers and defibrillators. With the ever increasing demand for efficiency and design, there is a need for ultrathin, safe and flexible energy storage options. A paper battery is a flexible, ultra- thin energy storage and production device formed by combining carbon nanotubes with a conventional sheet of cellulose based paper. A paper battery acts as both a high energy battery and supercapacitor, combining two components that are separate in traditional electronics.

This combination allows the battery to provide long term, steady power production and bursts of energy. Through the use of super capacitors, batteries can be made that will deliver renewable energy from bodily fluids such as blood or sweat. This technology can be greatly utilized by medical devices. It combines two essential materials, cellulose and carbon nanotubes (CNTs), that fit the characteristics of spacer and electrode and provide inherent flexibility as well as porosity to the system. Cellulose, the main constituent of paper and an inexpensive insulating separator structure with excellent biocompatibility, can be made with adjustable porosity. CNTs, a structure with extreme flexibility, have already been widely used as electrodes in electrochemical devices. 

By proper integration the output power of paper batteries can be adapted to required level of voltage–current. This cellulose based spacer is compatible with many possible electrolytes. Researchers used ionic liquid, essentially a liquid salt, as the battery’s electrolyte, as well as naturally occurring electrolytes such as human sweat, blood and urine. 

Due to the flexible nature of the cellulose and nanotubes, this power source can be easily modified or placed in the body or various medical devices. The need for surgery to replace batteries on internal medical devices would be nonexistent. This is because super capacitor does not show a loss in power dissipation over time like normal chemical batteries do. Patients with implanted medical devices will also benefit from the flexibility because previous devices may cause discomfort for person due to a larger solid power source. 

As this technology is adapted it will prove to be extremely useful and could even save not only cost but lives also.