Science & Tech

Researchers use water to create a safer and more durable EV battery cell

Lithium-ion batteries are the catalyst for our EVs, but they’re not perfect. Specifically, one of their main disadvantages is the flammability of the organic electrolytes currently used for their production.

Thankfully, hope is on the way. A team of researchers from Germany and Japan have developed a solution to fix this problem by replacing organic electrolytes with aqueous (water-based) ones.

Sounds simple, but it isn’t

At first thought, the use of water sounds like a very straightforward answer to the problem — water is by default inflammable.

But in reality, the integration of aqueous electrolytes into a battery cell has been problematic since 1994, when the idea was first tried out by scientists W. Li and J.R. Dahn.

What’s the difficulty?

The main disadvantage of aqueous lithium-ion batteries is their lower energy density compared to their conventional counterparts.

This problem originates from the narrow electrochemical stability window of aqueous electrolytes, so let’s take a moment to explain why this complicated-sounding window is so important. 

Understanding the chemistry of the problem

The electrolyte is the medium that enables the movement of lithium ions between the cathode (positive electrode) and anode (negative electrode) — basically what facilitates the entire electrochemical process needed for the EV battery to work.

EV battery structure