As the world moves towards a greener and more eco-friendly future for electric vehicles, their fundamental basis-batteries– need to be as sustainable as possible. Unfortunately, lithium-ion batteries, regarded as modern-day miracles, are not sustainable. This has led researchers to look for inspiration elsewhere, and what better inspiration than mother nature herself? This is especially true in this instance where crab shells are used to make sustainable batteries.

Researchers at the University of Maryland and the University of Houston have created a sustainable zinc battery with a biodegradable electrolyte derived from crab shells. This implies that we have been discarding the most valuable part of the crabs.

But before delving further, we must comprehend why the existing lithium-ion battery standard is not an environmentally sound choice before we can discuss more about sustainable batteries made using crab shells.

So, Why Not Lithium?

Although lithium-ion batteries are widely manufactured and utilized worldwide, they cause environmental problems. For instance, the degradation process for their polypropylene and polycarbonate separators could take hundreds or even thousands of years.

Source: Global lithium production capacities

Additionally, the electrolytes used in these batteries can be liquid, paste or gel. These are used to transport the ions between the two electrodes and are usually made from corrosive and combustible substances. They also have the potential to start fires at recycling facilities, in landfills, and on aeroplanes.

On the other hand, this novel battery employs a gel electrolyte manufactured from a biological substance called chitosan. The exoskeletons of crustaceans, such as crabs, shrimp, and lobsters, are the most common source of chitosan and are easily collected from seafood waste. It can also be found in the cell walls of fungi and squid pens.

So, what makes these crab shell batteries so special?

Zinc is more prevalent than lithium in the earth’s crust. Modern zinc batteries are more affordable and secure. Using water as an electrolyte provides more inherent safety than lithium-ion batteries. Unfortunately, zinc-ion batteries often cannot be charged repeatedly and perform poorly due to the water inside the battery corroding the zinc and forming deposits on the anode that interfere with the battery’s operation.

This is where sustainable batteries using crab shells come into play. Some of the problems with conventional zinc batteries that they can resolve include the following:

1. Reduced corrosion

The sustainable batteries produced from crab shells contain chitosan molecules that can form electrostatic complexes with other negatively charged synthetic or natural polymers. Since they bind strongly with water, fewer water molecules should be available to interact with the zinc, potentially lowering zinc corrosion.

Source: Eventual degradation of chitosan after conversion into a battery

2. 1000 Cycle

The scientist also tested the zinc-metal battery’s performance using this electrolyte and found that the cells could run for 400 hours with an energy efficiency of 99.7% after 1,000 cycles. This suggests that the battery might be used to store wind and solar energy before being fed into power grids.

3. Cost-effective alternative to landfills

The consumption of 1.5 million tonnes of crabs annually results in a waste product of 0.5 million tonnes of crab shells. This goes well beyond the current production of Lithium-ion battery electrode materials. These shells are frequently merely thrown into a landfill or the ocean, which is an expensive method of disposal that may cost more than $100 per tonne and is terrible for the environment because landfills themselves indirectly produce hazardous gas emissions.

4. Increased Biodegradability

A biodegradable electrolyte, by definition, allows for the breakdown of around 2/3 of the battery by microorganisms. However, within 5 months, this chitosan electrolyte entirely disintegrates. Instead of leaving behind lead or lithium, zinc is left behind, which is recyclable.

Source: Time-lapse showing complete degradation of battery after 5 months

Given the current energy scenario, it has become quite imperative that we decrease our dependency on fossil fuels and, consequently, the associated emission of greenhouse gases. This particular instance of crab shells used to make sustainable batteries is a remarkable strategy for creating clean and effective energy-storage devices. However, more research is required to make the prospective batteries entirely biodegradable and environmentally friendly.

Also Read: Can Batteries Blast Due To Rising Temperatures?