Turning bricks into batteries using nanotechnology

|Difficulty level: Medium|

In 2019, three scientists namely John B. Goodenough, M. Stanley Whittingham and Akira Yoshino shared the Nobel Prize in the field of chemistry. They won Nobel Prize for their work on Lithium-Ion Batteries, which can store a significant amount of energy. The largest lithium-ion batteries setup is Hornsdale Power Reserve, South Australia. Tesla Inc. built this capacity in September 2017 within 100 days. This system has a capacity of 100 megawatts and can store 129 megawatt-hours of energy from wind turbines. This figure is enough to supply 30,000 homes for eight hours.

Lithium-ion batteries are rechargeable and powerful with having 80% to 90% charging-discharging efficiency for 400-1200 cycles durability. Lithium-Ion batteries have enough potential to be useful in applications like mobile phones, laptops and Electric Vehicle. These are capable of storing significant amounts of energy from renewable sources like solar and wind energy.

Another widely used rechargeable batteries are Lead Acid Batteries. These have 50-95% charging/discharging efficiency over less than 350 cycles durability. These are comparably less costly. Motor vehicles, cell phone towers and off-grid household electric power systems use these batteries.

Need for batteries

Currently, non-renewable sources are used to generate electricity. This electricity is then transferred to a distant place for different purposes. We do not store electricity in the power grid or any other place. This makes the whole energy sector vulnerable to grid failure or any other accident. So, it is wise to store electricity locally using high capacity batteries.

Also, the generation of electricity from renewable sources requires a suitable environment condition. Solar cells can not be used in cloudy days or during the night. Similarly, the solar cell is less efficient at high altitudes where the sun appears only for a few hours. Wind turbines require constant strong air to generate consistent electricity. As the world is constantly shifting to renewable sources for its energy requirements, It is necessary to address these hurdles. Affordable batteries can be a solution to this, Where we can store energy when we can produce it and use it later when required. 

But, present batteries are not capable of storing a large amount of energy. The present technology can power appliances only for a few hours. Additionally, these technologies require high maintenance, space for the setup, marginal cost and are not eco-friendly. So, is there a better alternative?

Bricks as a power bank!

Traditional red fired bricks are building materials for the construction and architectural purpose which are made in furnaces and comprise of fused particles of silica (SiO2), alumina (Al2O3) and red colour providing hematite (α-Fe2O3).

But what if little nanotechnology added to these bricks?

It will result in our houses as a literal powerhouse someday that means our bricks will turn into super-batteries. This is the technology from Washington University, US. They use the porous nature of red fired bricks by filling them with tiny nano-fibres. This nano-fibre is of conducting plastic called PEDOT (Poly (3,4-ethylenedioxythiophene)). This PEDOT polymer acts as a capacitor for storing the charge. So, if this storing capacity increased to a favourable amount, bricks will turn into cheap super-capacitors. These bricks will store renewable energy having fast charging-discharging efficiency up to 10,000 cycles compared to lithium-ion batteries.

Procedure and Working

Insights into the procedure and working of these bricks involve the vapour synthesis in the presence of HCl vapour and EDOT solution in furnace about 160°C. The oxidative radical polymerization form PEDOT coating on the bricks which has high electrical conductivity, easy charge transfer and thus ideal path for producing electrodes. Connecting a Polythiophene (PT) current lead using polyimide tape turns the nano-fibrillar coated bricks to electrodes. While the entire module is coated with another epoxy, only exposed layers are cathode and anode. This indicates the Ohmic behaviour and resistance of about 7 Ω (has different value with different chemical involvements) and has an output voltage of 2.685V (charged at 4.5V for 15s) and lights a white LED for 11 minutes. Further, there is a gel electrolyte layer which prevents the bricks from short-circuiting. Also, it enhances adhesion with a shearing force equal to 1000 times the device’s weight.

The shock on touching bricks?

Definitely not if the temperature is between -20° C to 60° C. Outdoor exposure is inevitable with epoxy encapsulation which affords a cost-effective, mechanically robust and waterproof housing. The temperature below -20° C and above 60° C causes significant freezing and evaporation of water from gel. This leads to unstable electrical performance and breakage of the epoxy seal. A device charges to 3V in 10s while immersed in water and lights up the green LED (2.155V) for almost 10 minutes. This epoxy-coated superconductor retains 90% of original capacitance and almost 100% coulombic efficiency after 10,000 charging-discharging cycles. Thus constructed nano-fibrillar PEDOT coated brick wall has the potential to deliver maximum capacitance of 11.5 KFm-2 and energy density of 1.61 Whm-2.

Why these bricks?

There are many other types of batteries but these contain toxic elements. This can be hazardous to both mankind and the environment, thus mannerly disposing of is essential. Lithium-ion batteries mainly lack in terms of maintenance and manufacturing expenses which are 40% more than nickel-cadmium cells. Lead Acid Batteries have slow charging and discharging, loss of ability to charge if discharged for too long due to sulfation, risk of explosion etc. We also have alkaline batteries which don’t contain toxic elements but these are restricted to only small scale setups. These have a small life and may also get a leak.

But bricks turned to super-capacitors using nanotechnology can store large amounts of charge with fast charging/discharging efficiency. These bricks can also work in the water medium. The PEDOT polymer is eco-friendly and recyclable, which will not harm the environment. The upgraded technique to desirable parameters will make these bricks both cost and space-efficient.

So interested for the future powerhouse?

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Featured Image credits: D’Arcy Laboratory/Washington University in St. Louis.