Biobatteries: A green form of energy storage

The need for greener energy storage

Biobatteries are an exciting and rapidly developing technology that offer a promising solution to the limitations of traditional batteries. Unlike conventional batteries that rely on heavy metals and synthetic chemicals, biobatteries generate electricity through the chemical breakdown of organic compounds (such as sugars and starches).

One of the most compelling advantages of biobatteries is their potential for sustainability. The organic fuels used in biobatteries are often renewable, biodegradable, and widely available. Additionally, biobatteries can be designed to be non-toxic, flame-retardant, and even compostable, offering a stark contrast to the hazardous waste associated with disposal of traditional batteries.

As research continues to advance, biobatteries are showing increasing promise not only in terms of environmental impact but also in performance. With ongoing improvements in energy density, enzyme efficiency, and microbial engineering, biobatteries may soon rival or surpass traditional batteries in specific use cases.

Innovation in biobatteries

Sugar-powered biobatteries

One prominent type of biobattery uses sugars as the fuel source, with the chemical reactions catalysed by enzymes. In these biobatteries, electricity is generated by the oxidation of the sugar compounds via enzymes at the anode of the biobattery. Sony conducted the first research into enzyme-catalysed sugar biobatteries, with their research published in 2007.[1] In their pioneering research, Sony used glucose as the fuel source and produced a power output of 50 mW.

An example patent right associated with Sony’s research into sugar biobatteries is European patent no. 1630227, relating to an electrode comprising an immobilization carrier. The immobilization carrier is suitable for realizing a highly efficient functional electrode incorporating catalytic function of an enzyme. 

More recently, Dr. Y.H. Percival Zhang’s team at Virginia Tech has built on Sony’s research by developing a biobattery using maltodextrin as the sugar fuel source.[2] Maltodextrin has a higher energy density than glucose and thus is potentially a superior fuel source to glucose. Maltodextrin can also be derived from starch and is therefore a renewable resource. Dr. Zhang’s research involved the use of a combination of 13 enzymes to ensure maximal energy was extracted from the maltodextrin, enabling superior extractable energy density than traditional lithium-ion batteries.

European patent no. 3005461 is an example of a granted patent relating to a maltodextrin biobattery and listing Dr. Zhang as an inventor. European patent no. 300546 relates to a process for generating electrons from hexose sugars, when generating electricity in biobatteries. The process involves generating glucose 6-phosphate (G6P) and 6-phosphogluconate (6PG) by a chemical reaction of the hexose sugars with polyphosphate, ATP or free phosphate.

Bacterial biobatteries

Another type of biobattery involves the use of bacteria to catalyse biochemical reactions. For this type of biobattery, electricity is generated by bacteria anaerobically oxidising a fuel, such as sugar, at an anode. Research into bacterial biobatteries includes Prof. Seokheun Choi’s work at Binghampton University, utilising three types of bacteria that work together synergistically to generate electricity from a fuel source produced by bacterial photosynthesis.[3]

An example patent right associated with Prof. Choi’s research is U.S. patent no. 8,734,968. U.S. patent no. 8,734,968 relates to a microbial fuel cell including in part an electrically conductive biofilm formed on the anode and comprising anode-respiring bacteria comprising Geobacter sp.

Further work has included the recent development of dissolvable bacterial biobatteries, which after use can be harmlessly dissolved.[4] The creation of these dissolvable batteries provides significant environmental benefits compared to the disposal of traditional batteries.

Advancing biobattery design for a circular economy

An example of a prime innovation in the biobattery sector comes from Circular BioEnergy Technologies Ltd., led by Prof. Ulugbek Azimov of Northumbria University, based in Newcastle upon Tyne, United Kingdom.

Circular BioEnergy Technologies Ltd. is an award-winning Newcastle-based company, with their recent awards including Innovative Start-up of the Year. The company has developed the BioPower Cell, a form of biobattery that provides key environmental benefits over traditional batteries. The BioPower Cell is produced from fully recyclable organic materials and does not use materials common to traditional batteries, such as lithium, cobalt, or other rare earth metals. At the end of its lifespan, the BioPower Cell can be repurposed as ionic fertiliser.

This innovation therefore provides a green, biodegradable, rechargeable, and flame-retardant battery, meeting the requirements of the circular economy and with the possibility of revolutionising how we store sustainably generated electricity.