Research Highlights

A supercapacitor thinner than a human hair

Published online 9 May 2017

Scientists invent bendable supercapacitors that are thinner than a human hair.

Biplab Das

Batteries that usually power implantable devices such as pacemakers eventually run out of chemical reactants, requiring a surgery to replace them — a health hazard to cardiac patients. 

Now, a research team from Egypt and the United States has reportedly overcome this drawback by inventing ultrathin, biocompatible supercapacitors that can be used to make efficient and long-lasting batteries for implantable devices1.

“Besides pacemakers, the supercapacitors could be used to safely power a broad spectrum of implantable biomedical devices such as deep brain stimulators, biosensors and various other electronic devices,” says the study’s lead author Islam M. Mosa of Tanta University, Egypt. 

The scientists prepared the supercapacitors using graphene, a muscle protein and biofluids as electrolytes. Batteries made using such supercapacitors can power pacemakers for a long time by utilizing protein and biofluids available in the body. 

The supercapacitors, thinner than a human hair, can generate high power density. Unlike pure graphene which is potentially toxic to human cells, the graphene-protein hybrid material used in the supercapacitors showed no toxic effects on specific cultured cells. 

When allowed to charge and discharge for four days, the polymer-wrapped supercapacitors showed no harmful effects on cells. Even if they leak, it wouldn’t lead to any adverse effects. 

 They also retained their efficiency to charge and discharge even after being bent at an angle of 90° for 1000 bending cycles.


  1. Mosa, I. M. et al. Ultrathin graphene–protein supercapacitors for miniaturized bioelectronics. Adv. Energy. Mater. (2017).