Graphene Electrodes for Hybrids

摘要

RESULTS: Using graphene, a form of carbon made of sheets just a single atom thick, researchers have built ultra-capacitor electrodes that can store nearly as much energy as the electrodes now used in batteries for hybrid vehicles. The electrodes stored 86 watt-hours per kilogram. That would translate to 21 to 43 watt-hours per kilogram in a complete ultracapacitor, which would weigh more than just the electrode. Nickel-metal hydride batteries for hybrids store between 40 and 100 watt-hours per kilogram. WHY IT MATTERS: Automakers typically oversize the batteries in hybrids to make up for the loss of energy storage capacity over time as well as the fact that batteries can't be discharged completely without damaging them. Conventional ultracapacitors don't have this problem-they can be charged and discharged tens of thousands of times without losing much storage capacity-but they store just 5 to 10 percent as much energy as nickel-metal hydride batteries. The new high-energy