Flow battery – the new rechargeable, non-toxic and scalable energy storage

With the growth in investments in the renewable energy sector, need for efficient and cheap energy storage facilities has been on a sharp rise as this is critical in supporting the intermittent energy sources such as solar and wind.

Researchers from Harvard have been working on how to improve their latest version of their flow battery so as to make it more users friendly, economical, efficient and safe. Their main aim was to use non toxic elements and electrolytes so as to be able to make a flow battery that can easily be used at home even by people without technical skills.

The improvement of the 2014 flow battery uses cheap and abundant elements such as carbon, oxygen, iron and potassium in its construction s these compounds are not toxic and do not easily ignite which makes them safe for home use. These elements are mixed in water to form a solution that can store large amounts of electrical energy.

The new chemical composition of the battery was discovered by Michael Marshak and Kaixiang Lin in collaboration with Roy Gordon. They also added an organic dye together with an inexpensive food additive so as to increase the battery voltage by up to 50%. The fact that this model is non toxic, non flammable, inexpensive and high performance makes it one of its kinds in the market.

In flow batteries the capacity of the battery is determined by the size of the tanks that contain the liquids which means that the capacity can easily be increased and at a low cost which gives it an advantage over solid electrode batteries. The improvement which has made the flow battery non toxic and inexpensive to build has opened doors in the storage industry.

Another improvement is in the electrodes. Instead of using metal ions dissolved in acid, the new model uses organic carbon based molecules, quinones, which occur abundantly in nature. The quinones once dissolved in aqueous solutions form the negative electrode side while the positive electrode is made of ferrocyanide in alkaline conditions which has replaced the toxic and volatile bromine. The fact that ferrocyanide is non toxic and non corrosive. The fact that the battery conditions are in the alkaline state means that less expensive materials such as plastics can be used to make the battery.

This is a real game changer as the main factors that affect the energy storage industry are economics of production of the storage equipments as well as the applicability of these systems in large scale. This new model engineered by Harvard researchers offers solutions to both factors as it is cheap to make with very large storage capacities as well as non toxic which means that it can easily be used as household to store the renewable energy that they produce.