Battery Show North America 2023 | Report E-Mobility Engineering | November/December 2023 49 “But because it’s self-limiting, it will only react with one atomic layer at a time. Then we will change out whichever precursor we’re dosing into the reaction bed based on which stage of the cycle we’re in. We control the number of cycles and the thickness.” Forge Nano is becoming a cell producer in the US using its Atomic Armor technology and in-house developed formulations to enable the US to compete in lithium-ion battery manufacturing, Dr Travis said. Arkema discussed its Kynar polyvinylidene fluoride (PVDF) binder for lithium-ion battery cells, which is formulated to resist high voltages and aggressive cell chemistries such as NMC, along with a new acrylic binder that is flexible enough to accommodate the swelling of silicon-rich anodes in LFP cells. Both binders are waterborne. In a cell, the binder sticks the active material particles to each other at the anode and cathode sides, to their foil substrates and to the separator between the anode and the cathode. The binder does more than this, however. “It wets faster, so you accelerate your manufacturing process, and you have less contact resistance, so you have better performance and better longevity,” Mickael Havel explained. “Kynar PVDF also has a chemical affinity with fluorine-based electrolytes such as LiPF6 and LiFSI. Arkema’s Foranext LiFSI accelerates the flow of ions through the electrolyte and across the separator during charging and discharging, which is especially needed for fast charging,” Havel said. The Kynar PVDF binder is also compatible with the ceramic coatings that some cell manufacturers use to enhance the dimensional stability of the separator, thereby reducing the risk of short-circuits between the anode and the cathode. “Our PVDF could be inside that layer of ceramic, a constituent of it, or it could be put on as a top-coat,” Havel said. “In that case it is called a sticky separator, because when you put the anode, separator and cathode together at high speed you want good adhesion between them so that you don’t get any sliding that could cause a short.” For lower voltage cell chemistries such as LFP, Arkema has launched a range of acrylic-based binders, dispersants and rheology additives it calls Incellion. The acrylic binder, for example, allows greater use of silicon in the cell anode. Silicon accommodates more lithium ions, enabling the anode to hold a bigger charge, but swells in the process so that the cell ‘breathes’ through the chargedischarge process. “You need a binder that can accommodate that breathing – expanding, contracting – without cracking,” Havel said. Wildcat Discovery Technologies showcased its high-throughput r&d platform, which is modelled on drug discovery techniques used by the pharmaceuticals industry and is designed to accelerate battery innovation through projects with automotive OEMs and cell manufacturers to test new chemistries. The company is also using the platform to develop its own active materials. “We’re able to do many experiments in parallel and get results quite fast,” Jim Voeffray explained. “Over the last 15 years, the company has automated the testing of multiple slight variations on different chemical recipes at the same time, typically incorporated into small pouch cells and mounted in test towers. “Now we have updated our strategy to where we’re going to enter the market as a battery materials supplier focused on cathode materials.” The first materials the company will offer will be LFP formulations, followed by lithium manganese iron phosphate. The latter promises better performance in terms of energy density and power density, with comparable cycle life and costs to LFP cathode chemistries. The plan is to follow these with a proprietary cathode material based on disordered rock salt, a high-energy material without the nickel or cobalt, and capable of competing with highnickel NMCs and of serving as a drop-in replacement for an NMC cathode in any cell. “We’ve been working on disordered rock salt for the past 7 years and now we can see a path to commercialisation,” Voeffray said. “We’re probably a year away from having something customers can sample. Incellion is Arkema’s new family of acrylic-based binders, dispersants and rheology additives
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