Flint wants to disrupt the battery industry with paper

Lithium-ion batteries have become the standard in the electrification revolution. In fact, they’ve become so indisputably integral to battery development that everyone from government to automakers to big oil is racing to secure access to the ore.

The only problem is that mining lithium is expensive, time-consuming, and labor-intensive. And this extraction process has harmful consequences on the environment. The same goes for other materials used in the composition of a battery, such as nickel, cobalt and graphite.

A handful of startups have emerged to tinker with different chemistries in an effort to build more efficient, lighter and more environmentally friendly batteries. They generally replace some of the standard materials, but rarely forgo lithium.

Enter Flint, a Singapore startup that claims to have found a way to replace the lithium in a battery with paper.

“Paper batteries are very new in this world, and only a few institutions are currently working on this technology,” Carlo Charles, co-founder of Flint, told TechCrunch. “We are working to change the materials: instead of fusing lithium, nickel and cobalt, we use zinc, manganese and cellulose papers. With these three elements, we can change the way the battery can be used, while maintaining the way the battery is manufactured. So this is an advantage that we have over other battery strategies and technologies.

Flint, which participated in the TechCrunch Disrupt 2023 Startup Battlefield, only started producing its paper batteries in 2022, but the company already has a prototype. Initial tests have shown promise, and Flint now wants to find partners with whom to test its paper batteries in consumer products.

It looks good, but how does it work?

First you need to understand a little about normal lithium-ion batteries. They are made up of four components: the anode (the negative electrode), the cathode (the positive electrode), the separator and the electrolyte. The electrolyte, which is a liquid material, sits in the middle and acts as a messenger, moving ions between the electrodes during charging and discharging.

The Flint battery has only three components: a zinc-based anode, a manganese-based cathode and the paper separator. Flint coats his paper with cellulose, its anode and cathode with hydrogel before baking it in a vacuum oven, creating a hydrogel-reinforced cellulose paper. Hydrogel is a “smart” material that can change its structure in response to its environment, such as temperature, pH, salt or water. This is also Flint’s secret sauce because it allows the transfer of electrons between the anode and cathode without the need for both the separator and the electrolyte.

And apparently it works – well enough that even if the battery chemistry is changed, the structure and manufacturing process of the battery remains the same. In other words, Flint’s batteries may one day be used interchangeably with today’s lithium batteries, Charles says.

“We can just take existing technologies that already exist, integrate them into our recipe, and easily have a production line with paper batteries,” the co-founder said, noting that other solutions like hydrogen batteries or sodium require a change in procedure. a product is produced. “The great thing about us is that we make it easy for manufacturers and suppliers to replace old lithium batteries with our paper batteries. »

Charles said Flint chose zinc and manganese over lithium, cobalt and nickel because the former two are more abundant materials, which is important when talking about sustainability in the battery industry. He added that they are also safer materials than those used in current batteries, which are very reactive. You only need to look at the numerous battery fires caused by lithium batteries to see that safer critical materials are an attractive prospect.

“You can literally shut off our battery while it’s operating, and it will continue to operate without overheating or exploding like what we expect from lithium batteries,” Charles said.

The materials used in Flint’s paper batteries also allow them to operate in a temperature range of minus 15 degrees Celsius to 80 degrees Celsius, opening up a wider range of product possibilities and providing an example of how The effectiveness will not deteriorate over time. Current battery materials, he explained, can only operate at temperatures between 15 and 35 degrees Celsius.

“Lithium batteries are really good in terms of weight, capacity and volume, but they are not as effective in terms of cost and safety,” Charles said.

Flint’s paper batteries advance cost and safety, and they already meet lithium battery standards for voltage and current. But paper batteries still have a long way to go to reach the capacity of lithium batteries. Specifically, Flint needs to increase the volumetric density of its batteries.

“So if you turn that paper battery into an AA battery, for example, we can only provide about 60 to 70 percent of the energy density of a lithium battery,” Charles said. “So we are focusing on two things. The first is to increase this number to a higher standard. And secondly, it’s to see if there are applications that could be used today with these numbers, where the energy density is not so important.

Flint also needs to improve the life cycle of its batteries before it can bring them to market. Charles claims that a lithium battery that has been tested for 2,000 life cycles would see its health depreciate by up to 60%. Flint only has the resources to test 1,000 life cycles, but during those life cycles the battery health drops to 70%.

Charles said he was proud of what his small team of five employees and four advisors was able to accomplish, given Flint’s limited resources. The startup invested $50,000 and the Singapore government gave it another $100,000. With this, Flint was able to MacGyver create a clean room together to make batteries and test them.

Batteries must be manufactured in rooms so clean and dry that it is impossible to find a speck of dust or a drop of moisture. The conditions must be precise and the machines involved are usually automated. Charles jokingly described the “very open environment” in which Flint produces its prototypes today as “exactly where you shouldn’t be making batteries.”

“I went to a battery factory recently and they have this big sludge machine that you put the powders in to turn them into liquid, and they run this huge machine, which is almost half the size of my room, and they make it work. 12 hours just to make a single mud component,” Charles said. “Do you know what we do to make our batteries? We use an egg beater and beat it for three hours with our hands. And our numbers are correct despite all this. Imagine if we had the resources and facilities.

Moving from prototype to product

Flint is in the final stage of its journey to optimize battery chemistry. From there, the company will soon be ready to move into manufacturing and production and try to get other companies to use Flint paper batteries in their products.

To initially get to a point of scale, Charles said Flint will need to focus on two of three criteria: weight, capacity and volume. If the startup sacrifices getting the weight right to focus on reducing volume and increasing capacity, it can try commercializing energy storage systems (ESS). Flint already works with one of the largest ESS suppliers in Singapore, according to Charles.

The company could also sacrifice capacity and focus more on building batteries that are lighter and smaller, which would present the ideal application for remote sensors and wearable devices.

The long-term vision would be to figure out how to sacrifice volume, increase capacity and reduce weight, making batteries more suitable for electric vehicles.

“We are in talks with Airbus, which is trying to electrify its planes for the future,” Charles said. “Ultimately, we would like to be able to help them and manufacture batteries with personalized shaping, because they are made of paper and flexible. They could be shaped like a wing or the entire curved body of the plane.