There are lithium-ion batteries It became the standard in the electrification revolution. In fact, it has undoubtedly become such an integral part of battery development that everyone from government to automakers to major oil companies are rushing to support access to the metal.
The only problem is that lithium is expensive, time-consuming and labor-intensive to extract. This extraction process negatively affects the environment. The same applies to other materials that go into making a battery, such as nickel, cobalt, and graphite.
A host of startups have emerged to tinker with different chemistries in an attempt to build more efficient, lightweight, and environmentally friendly batteries. They usually replace some of the standard materials, but rarely do they completely abandon reliance on lithium.
Enter Flint, a startup from Singapore that says it has found a way to replace the lithium in a battery with paper.
“Paper batteries are very new in 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 incorporating lithium, nickel and cobalt, we are using zinc paper, manganese and cellulose. With these three things we can change the way a battery can be used, but maintain how the battery is made. So, this is the upper hand that we compare to strategies and technologies.” Other batteries out there.”
Flint, which participated in TechCrunch Disrupt 2023 Startup Battlefield, only started producing its paper batteries in 2022, but the company already has a prototype. Initial tests were promising, and now Flint wants to find partners to test its paper batteries in consumer products.
Sounds good, but how does it work?
First you need to understand a little about regular lithium-ion batteries. It consists of four components: anode (negative electrode), cathode (positive electrode), separator and electrolyte. The electrolyte, a liquid substance, is located in the middle and acts as a conductor, moving ions between the electrodes when charging and discharging.
A flint battery consists of only three components: a zinc-based anode, a manganese-based cathode, and a paper separator. Flint encapsulates the cellulose paper, anode and cathode in a hydrogel before baking it in a vacuum oven, in effect creating the hydrogel-reinforced cellulose paper. A hydrogel is a “smart” material that can change its structure in response to its environment, such as temperature, pH levels, salt or water. It is also Flint’s secret sauce because it enables electron transfer between the anode and cathode without the need for both a separator and an electrolyte.
It obviously works well, since while the chemical composition of the battery is changed, the battery structure and manufacturing process remain the same. In other words, flint batteries could one day be used interchangeably with today’s lithium batteries, Charles says.
“We can just take existing technologies that already exist, put them in our recipe, and we can easily have a production line with paper batteries,” the co-founder said, noting that other solutions like hydrogen or sodium batteries would require a change of method. The product is manufactured. “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 discussing sustainability in the battery industry. They are also safer materials than those used in batteries today, which are highly reactive, he said. One need look no further than the numerous battery fires sparked by lithium batteries to see that safer materials represent an attractive prospect.
“You can literally cut your battery off while it’s running, and it will still work without overheating or exploding like we expect lithium batteries to do,” Charles said.
The materials used in paper flint batteries also allow them to operate in a temperature range of 15°C to 80°C, opening up a greater range of product possibilities and providing an example of how efficiency does not deteriorate over time. He said that the materials in batteries today can only operate at a temperature of 15 degrees Celsius to 35 degrees Celsius.
“Lithium batteries are really good in terms of weight, capacity and size, but they are not cost-effective and safety-wise,” Charles said.
Paper flint batteries move things forward in terms of cost and safety, and they already meet lithium battery standards when it comes to voltage and current. But paper batteries have a long way to go to match the capacity of lithium batteries. Specifically, Flint needs to increase the bulk density of its batteries.
“So, if you convert this paper battery into an AA battery, for example, we can only save about 60% or 70% of the energy density of a lithium battery,” Charles said. “So we’re focusing on two things. Number one is to get that number even higher. Number two is to see if there are any applications that can be used today with those numbers, where the power density isn’t so important.”
Flint also needs to improve the cycle life of its batteries before bringing them to market. Charles says that a lithium battery that has been tested over 2,000 life cycles will see its health reduced to 60%. Flint only has the resources to test 1,000 life cycles, but during those life cycles, battery health drops to 70%.
Charles noted that he is proud of what his small team of five employees and four consultants has been able to accomplish, given Flint’s limited resources. The startup received $50,000 and was awarded another $100,000 by the Singapore government. With this Flint was able to put together a clean room for MacGyver to make and test the batteries.
Batteries must be manufactured in very clean and dry rooms so that not a speck of dust or a hint of moisture can be found. 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 “a place where batteries shouldn’t be made.”
“I recently went to a battery factory and they had this big slurry machine where they put powders into liquid form, and they turn on this huge machine, which is about half the size of my room, and they run 12 hours just to make one component of slurry,” Charles said. “Do you know what we do to make our batteries? We use an egg beater and beat it with our hands for three hours. Our numbers are good even with all that. Imagine if we had the resources and facilities.”
Moving from prototype to product
Flint is in the final stage of its journey to improve battery chemistry. From there, the company will soon be ready to get into manufacturing and production, and try to convince other companies to use flint batteries in their products.
To get to the point of measurement initially, Charles said Flint would need to focus on two of the following three criteria: weight, capacity and size. If a startup sacrifices getting the right weight to focus on reducing size and increasing capacity, it can try to go to market with energy storage systems (ESS). Flint already works with one of the largest ESS providers in Singapore, according to Charles.
The company could also sacrifice capacity and focus more on building batteries with lower weight and volume, which would make an ideal application for remote sensors and wearable devices.
The long-term vision is to figure out how to sacrifice size, increase capacity and reduce weight, making batteries more suitable for electric vehicles.
“We have been in talks with Airbus, which is trying to electrify its aircraft for the future,” Charles said. “In the long term, we would like to be able to help them and make batteries with custom shapes, because they are paper and flexible. They could be shaped like a wing or the entire curved body of an aircraft.