Researchers from Pondicherry University, Puducherry and SRM University, Chennai have recently demonstrated a novel device made of Nickel/ Nickel oxide (Ni/NiO) and graphene that could be used to store hybrid-energy.
The rising use of alternative and renewable energy sources also increases the need to store enormous amounts of energy. Unlike fossil fuels, which can be burnt when there is a need for the energy, renewable sources, like solar and wind, is only available intermittently. Using these sources efficiently requires devices like batteries and supercapacitors to store the energy when it is generated. However, battery technology, unlike other technologies, has not seen huge advancements.
In the new study, the scientists studied the properties of Ni/NiO anchored on graphene oxide. Using a mixture of nickel nitrate and citric acid at a mixture ratio of 1:1, nanoparticles of Ni/NiO were formed. These nanoparticles demonstrated high specific capacity (around 158C/g)- a measure of how well an object can charge and discharge. Next, the Ni/NiO nanoparticles were anchored on to a substrate made of reduced graphene oxide (rGO) using a method called probe sonication, where sound waves are used to agitate the nanoparticles and help them stick to the rGO surface. With the nanoparticles attached to the graphene surface, the specific capacity of the apparatus shot up to 335 C/g to almost twice as before. The new device Ni/NiO @rGO, also showed improved cycling stability, high rate capability and Coulombic efficiency, properties which allows it to charge and discharge efficiently, with minimal loss and high stability.
The researchers constructed a rudimentary supercapacitor or energy storing device with the Ni/NiO @rGO as the positive electrode, rGO as the negative electrode and a thin layer of dried gel made of polyvinyl alcohol (PVA), separating the two, acts as the electrolyte, and. The set up was then used to light up LEDs to demonstrate its storage and discharge capabilities, with the device storing higher amounts of energy than conventional devices. The study opens new avenues into hybrid energy storage devices that allows for a new generation of efficient batteries that can power the next generation of our gadgets.