Monash University researchers have brought next generation energy storage closer with an engineering first – a graphene-based device that is compact, yet lasts as long as a conventional battery.
A research team led by Professor Dan Li of the Department of Materials Engineering has developed a completely new strategy to engineer graphene-based super capacitors (SC), making them viable for widespread use in renewable energy storage, portable electronics and electric vehicles.
SCs are generally made of highly porous carbon impregnated with a liquid electrolyte to transport the electrical charge. Known for their almost indefinite lifespan and the ability to re-charge in seconds, the drawback of existing SCs is their low energy-storage-to-volume ratio – known as energy density. Low energy density of five to eight Watt-hours per litre, means SCs are unfeasibly large or must be re-charged frequently. Professor Li’s team has created an SC with energy density of 60 Watt-hours per litre – comparable to lead-acid batteries and around 12 times higher than commercially available SCs. A charged unit will operate 12 times longer than ordinary super capacitors, before needing to be recharged, which is the same amount of time for when a lead acid battery needs to be recharged. So, energy density is the same for this super capacitor as for batteries, but it still has the power density of ordinary capacitors (much shorter charge/discharge cycles than a battery is capable, and a greater tolerance for numerous– hundreds if not thousands– of charge/discharge cycles.
“It has long been a challenge to make SCs smaller, lighter and compact to meet the increasingly demanding needs of many commercial uses,” Professor Li said. Graphene, which is formed when graphite is broken down into layers one atom thick, is very strong, chemically stable and an excellent conductor of electricity.
A research team led by Professor Dan Li of the Department of Materials Engineering has developed a completely new strategy to engineer graphene-based super capacitors (SC), making them viable for widespread use in renewable energy storage, portable electronics and electric vehicles.
SCs are generally made of highly porous carbon impregnated with a liquid electrolyte to transport the electrical charge. Known for their almost indefinite lifespan and the ability to re-charge in seconds, the drawback of existing SCs is their low energy-storage-to-volume ratio – known as energy density. Low energy density of five to eight Watt-hours per litre, means SCs are unfeasibly large or must be re-charged frequently. Professor Li’s team has created an SC with energy density of 60 Watt-hours per litre – comparable to lead-acid batteries and around 12 times higher than commercially available SCs. A charged unit will operate 12 times longer than ordinary super capacitors, before needing to be recharged, which is the same amount of time for when a lead acid battery needs to be recharged. So, energy density is the same for this super capacitor as for batteries, but it still has the power density of ordinary capacitors (much shorter charge/discharge cycles than a battery is capable, and a greater tolerance for numerous– hundreds if not thousands– of charge/discharge cycles.
“It has long been a challenge to make SCs smaller, lighter and compact to meet the increasingly demanding needs of many commercial uses,” Professor Li said. Graphene, which is formed when graphite is broken down into layers one atom thick, is very strong, chemically stable and an excellent conductor of electricity.