Wind and solar power are increasingly popular sources for renewable energy. Unfortunately, intermittency issues keep them from connecting widely to the national grid. One potential solution involves the deployment of long-duration battery technology such as the redox flow battery. Despite its great promise, the current costs of this system are a key determining factor to real-world adoption.
Researchers have found a way of enhancing hybrid flow batteries or regenerative fuel cell (RFC) technology that could store electricity for very long durations for about one-fifth the cost of current storage technologies, with flexibility in siting and with minimal environmental impact.
They enhanced three hybrid flow cells using nitrogen-doped graphene (exposed to nitrogen plasma) in a binder-free electrophoresis technique (EPD). The technology combines carbon-based electrodes with economically sourced electrolytes, (manganese or sulphur, which are abundant chemicals in the planet) by means of a simple and yet highly effective electrophoretic deposition of nanocarbon additives (nitrogen-doped graphene) that enhance the electrode durability and performance significantly in highly acidic or alkaline environments.
The hybrid flow battery’s total chemical cost is about 1/30th the cost of competing batteries such as lithium-ion systems. Scaled-up technologies may be used to store electricity from wind or solar power for multiple days to entire seasons. These batteries are also extremely useful for grid-scale load leveling applications as their design is very flexible due to their unique feature of sizing power independently of their energy.
The energy density of a hybrid flow battery, especially the polysulphide/air system (S-Air), is 500 times higher than pumped hydroelectric storage. It is also much more compact and can be placed near any renewable generation.