Lithium-ion batteries have become the standard in the electrification revolution. In fact, they have become so undeniably integral to the development of batteries that everyone from governments to automakers to big oil is racing to increase access to the mineral.
The only problem is that lithium is expensive, it takes time and effort to extract it. And that extraction process takes a huge toll on the environment. The same applies to other materials that go into batteries, like nickel, cobalt and graphite.
A handful of startups have emerged to tinker with different chemistries in an effort to create more efficient, lighter, and environmentally friendly batteries. Usually they swap out some standard materials, but rarely do they abandon relying on lithium altogether.
Enter Flint, a Singapore startup that says it has come up with a way to replace lithium in batteries with paper.
“Paper batteries are very new to this world, and there are only a few organizations working on this technology right now,” Flint co-founder Carlo Charles told TechCrunch. “We are working on changing the materials, so instead of mixing lithium, nickel and cobalt, we are using zinc, manganese and cellulose paper. Those three things can change the way we use batteries, but keep in mind how batteries are made. So this is a better position for us compared to other strategies and battery technologies.”
Flint, which participated in TechCrunch Disrupt 2023 Startup Battlefield, only begins production of its paper battery in 2022, but the company already has a prototype. Initial tests have been promising, and now Flint wants to find partners with which to test its paper batteries in consumer products.
Sounds good, but how does it work?
First you need to understand a little about common lithium-ion batteries. They are composed of four components: anode (negative electrode), cathode (positive electrode), separator, and electrolyte. The electrolyte, which is a liquid, sits in the middle and acts as a courier, transferring ions between the electrodes during charging and discharging.
Flint’s battery consists of only three components: a zinc-based anode, a manganese-based cathode, and a paper separator. Flint coats its cellulose paper, anode and cathode, in hydrogel before baking it in a vacuum oven – essentially 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 level, salt or water. This is also the secret sauce of flint because it enables electron transfer between the anode and cathode without the need for both a separator and an electrolyte.
And apparently it works – so well that, while the chemical composition of the battery changes, the battery’s structure and manufacturing process remain the same. In other words, Flint’s batteries could, one day, be used interchangeably with today’s lithium batteries, Charles says.
“We can use existing technologies that already exist, put in our recipe, and easily build a production line with paper batteries,” the co-founder said, noting that hydrogen or sodium Other solutions such as batteries need to be replaced once a product is made. “The best thing about us is that we are making it so easy for manufacturers and suppliers to replace old lithium batteries with our paper batteries.”
Charles said Flint chose zinc and manganese instead of lithium, cobalt and nickel because the former two are more abundant materials, which is important when discussing sustainability in the battery industry. He said these are safer materials than those used in today’s batteries, which are highly reactive. One need look no further than the numerous battery fires involving lithium batteries to see that securing critical materials is an attractive prospect.
“You can literally disconnect our battery during operation, and it will still continue to work without overheating or exploding as we expect from lithium batteries,” Charles said.
The material used in Flint’s paper batteries allows them to operate in a temperature range of negative 15 °C to 80 °C, opening up a huge range of product possibilities and providing examples that do not reduce efficiency over time. Will not happen. The materials in today’s batteries can only operate at temperatures ranging from 15 degrees Celsius to 35 degrees Celsius, he said.
“Lithium batteries are really good in terms of weight, capacity and volume, but they are not as efficient in terms of cost and safety,” Charles said.
Flint’s paper batteries move the needle in terms of cost and safety, and they already match lithium battery standards when it comes to voltage and current. But paper batteries still have a long way to go to match the capacity of lithium batteries. In particular, Flint needs to increase the volumetric density of its batteries.
“For example, if you roll this paper battery into an AA battery, we can only provide about 60% or 70% of the energy density of a lithium battery,” Charles said. “So we are focusing on two things. Number one is raising this number to a higher standard. And number two is seeing if there are any applications that can be used with these numbers today, where energy density is not so important.
Flint also needs to improve the lifecycle of its batteries before they can come to market. Charles says that a lithium battery that has been tested over 2,000 life cycles will see its health degrade by up to 60%. Flint only has the resources to test for 1,000 life cycles, but during those life cycles, the battery’s health drops to 70%.
Charles said he is proud of what his small team of five employees and four consultants has been able to accomplish despite Flint’s limited resources. The startup bootstrapped $50,000 and the Singapore government gave it an additional $100,000. With this, Flint is able to work with MacGyver to create and test batteries.
Batteries should be manufactured in rooms that are so clean and dry that neither a particle of dust nor a trace of moisture can be found. Conditions must be precise, and the machinery involved is usually automated. Charles jokingly described the “very open environment” in which Flint produces its prototypes today as “exactly where you shouldn’t make batteries.”
“I recently went to a battery plant and they have this big slurry machine where you put the powder in to turn it into a liquid form, and they run that huge machine, which is about half the size of my room. , and they run it It took 12 hours to make just one slurry component,” Charles said. “Do you know what we do to make our batteries? We use an egg beater, and we They beat us with their hands for three hours. And despite all this, our numbers are fine. Imagine if we had the resources and facilities.”
Moving from prototype to product
Flint is in the final stages of its journey to optimize the battery’s chemistry. From there, the company will soon be ready to move into manufacturing and production, and try to inspire other companies to use flint paper batteries in their products.
To initially reach a point of scale, Charles said Flint would need to focus on two of the following three benchmarks: weight, capacity and volume. If the startup sacrifices weight reduction to focus on reducing volume and increasing capacity, it may try to go to market with energy storage systems (ESS). According to Charles, Flint is already working with one of the largest ESS providers in Singapore.
The company could also sacrifice capacity and focus more on creating batteries with lower weight and volume, which would present ideal applications for remote sensors and wearable devices.
The long-term approach 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. “Long term, we would like to be able to help them and make custom shaped batteries, because they are papery and flexible. They may be shaped like a wing or the entire curved body of the aircraft.