Bio-battery: The future of energy storage

            The demand of energy is increasing day by day with growth of world population. The dependence for energy on fossil fuel must be shifted to other renewable energy sources to protect our environment. But, the striking challenge for most of the renewable energy system is its storage capacity. High energy, high power density and availability of eco-friendly materials are the major criteria for a superior storage device. So a good combination of renewable energy technologies and improved energy storage devices play an important role in energy distribution of developing countries especially in rural area. So, intensive research for efficient energy storage system is in high demand.



        One of the most convenient portable sources of energy storage device  is a Battery.   A battery in general is a device which converts the chemical energy into electrical energy in the electrical field. There are several different types of batteries used in electronic and electrical devices. However, these different types of batteries come with highly toxic chemicals including compounds of mercury and lead which have very harmful effect on environment. Apart from that, the conventional batteries having toxic chemicals are very much prone to leakages and deadly explosions. So we need an energy storage device which contains non-toxic, eco-friendly elements along with all the superior quality present in a battery.

       Generally bio-battery is a special kind of energy storing device which is powered by organic compounds such as glucose, fructose, sucrose etc. It is well known to us that our human blood contains glucose. When enzymes present in human bodies break down glucose, several electrons and protons are released in that process which are source of negative and positive charges. Thus,   bio-batteries directly obtain energy from glucose by breaking it with help of enzymes and store that energy for future use.[1] This concept is almost identical to the process by which both plants and many animals obtain energy. So, Bio-batteries can be termed as alternative energy devices based on bio-electro catalysis of natural substrates by enzymes or microorganisms. Bio-Battery produces electricity from different renewable fuels providing a sustained, on-demand portable power source. Bio-batteries should be rigorously tested before being commercially sold. For that reason, several research teams, scientists and engineers are working to further advance the improvement of these batteries.

           Like all other cell battery, bio-batteries also consist of an anode, cathode, separator and electrolyte with each component layered over other. Anodes and cathodes are the positive and negative terminals respectively on a battery. Electrons enter the battery from anode terminal and flow out from the battery towards cathode terminals. We get current towards anode from cathode. In bio-battery biological enzymes are used for anode and cathode catalyst. Electrolyte along with separator lies between anode and cathode. The main utility of the separator is to keep the cathode and anode fully separated so that no electrical short circuits can take place. Good quality separator is needed otherwise the battery will burn by short-circuit.




 In this system glucose is used on anode side whereas enzymes are used on cathode side. Glucose gets broken into protons(H+) and electrons(e-) which are source of positive and negative charges.The protons move toward cathode side through separator and electrons move towardscathode side through mediator. Simultaneously, enzymes are used at cathode area which produces water using both electrons and protons transported from anode part. Oxygen reduction reaction took place which will create electrons (e-) and protons (H+) in the system. The system as a whole, allows for a flow of protons (H+) and electrons (e-) which ultimately generates electricity[2].





 The operation of Bio batteries are greatly dependent on the amount of glucose available. This glucose (sugar) can be afforded from nearly anything, including soda, waste materials, or the glucose in living organisms. The decomposition of materials to glucose is the main step in getting the cyclestarted.  By usingenzymatic hydrolysis process we can convert materials into glucose. Actually, enzymatic hydrolysis is the simple process in which cellulose is converted to glucose by the addition of different enzymes. Once glucose is present, oxygen and other enzymes can act on it to further generate protons and electrons. So bio-battery can use some excellent source of energy such as glucose, fructose, sucrose, dextrose to generate electrical energy. Generally sugar molecules are energy dense,easy to transport and cheap to digest. Every living cell on earth generates its energy from glucose. A group of researcher from Virginia Tech has developed a sugar powered fuel cell which can store 10 times more energy than lithium ion battery. This cell is refillable with maltodextrin solution and it only by products are electricity and water.
Depending on what type of agent is used to breakdown substrate, there are generally two types of Bio-battery- Enzymatic and Microbial.In Enzymatic Bio-Battery, enzymes (Biochemical agents) are used for breakdown of substrate and produce electricity. In Microbial type micro-organisms (escherichia coli etc.) are used for breakdown of substrate. Some of other types of Bio-battery include cellulose based bio-batteries, body fluid based bio-batteries etc.
Advantages
Bio battery has several advantages over conventional batteries. Among all the most important advantage of bio battery is that it provides instant recharge. Bio battery has high energy density and it can be operated at room temperature.These batteries keep themselves well charged with the help of continuous supply of glucose or sugar. They can automatically recharge themselves without external power supplyif the supply of sugar to the bio battery is kept constant. Bio batteries are source of nonflammable and non-toxic fuel. They does not create leakage and hence safe to use. The hazards of toxic fuel on the environment are well known by everybody so it upturns the importance of bio battery for green environment. 
Disadvantage:
Conventional batteries are able to retain energy for a much longer time. The disadvantage of bio battery is that they cannot retain energy for long time which make them unreliable storage system to be used for a longer time. A lot of research is going on in this field so that the ability of the bio battery to retain the energy for a much longer time may be increases significantly.
Bio battery has great potential to be used in different devices such as portable charging in cell phones, generators, remote power, medical implants e.g. pacemakers, insulin pumps etc.

1. "Bio Battery" (https://www.sony.net/SonyInfo/News/Press/200708/07-074E/inde
x.html). Sony Corporation.

2.Kannan, Renugopalakrishnan; Filipek, Audette; Li, Munukutla. "Bio-Batteries
and Bio-Fuel Cells: Leveraging on Electronic Charge Transfer Proteins", American Scientific Publishers.  

No comments:

Post a Comment