But due to the way it is produced, most of the pores within it aren't interconnected, limiting the material's ability to transport electricity. Now researchers at Stanford University have created a "designer carbon" with greater pore connectivity and therefore greater electronic conductivity, which enables superior energy-storage performance.

Used for everything from gas and water purification to air filters and medicine, activated carbon is generally produced from coconut husks, nutshells, peat, wood and other carbon-rich source materials. These are burnt at high temperatures and then subjected to either physical (aka steam) activation or chemical activation to create nanosized pores. But the random nature of these processes results in a material with little interconnectivity between the pores.

"With activated carbon, there's no way to control pore connectivity," says Zhenan Bao, the senior author of the study and a professor of chemical engineering at Stanford.