Lithium Bis(fluorosulfonyl)imide stands out with its recognizable white or off-white crystalline appearance. Its chemical formula, LiN(SO2F)2, gives a hint about the tightly woven atomic structure. Lithium ions, nitrogen, sulfur, oxygen, and fluorine come together to build a robust salt. Often called LiFSI, this compound made its way into advanced battery technology, particularly energy storage and electric mobility. Manufacturers value its unique traits—excellent conductivity, high solubility, and strong thermal stability. These aren’t just technical checklists, they translate directly into devices staying charged longer and holding up under stress, whether on a test bench or out on the road.
LiFSI doesn’t hide in one form. Laboratories and industries work with it as flakes, fine powder, crunchy crystals, pearls, and sometimes as a concentrated solution. This flexibility opens doors across industries. Battery designers look for LiFSI’s efficiency in both liquid electrolytes and novel solid-state systems, seeking reliable charge-carrying action and less battery swelling. It finds a comfortable home in lithium-ion and lithium-metal secondary batteries. From consumer gadgets to electric vehicles, these batteries must meet growing demands for safety, speed, and storage. Using LiFSI makes it easier to push for advances that matter—longer trips, less maintenance, more reliability. Sometimes, LiFSI even steps into the world of specialty polymers and advanced lubricants, showing the versatility raw materials bring to industrial design.
At the core, the molecular weight sits at around 187.07 g/mol. Its crystalline structure gives LiFSI a distinct look—sharp-edged, often sparkling when pure. Its melting point clocks in near 124°C, meaning standard room temperatures keep it solid. Unlike some lithium salts, LiFSI can withstand temperature swings without rapid decomposition. Its density runs close to 1.5 g/cm3, offering a substance that’s neither too heavy nor too airy for controlled application. You’ll often find it in high-purity solid form, though liquid solutions make handling and integration into batteries much simpler in automated settings. Solubility matters here. LiFSI dissolves well in common organic carbonates like ethylene carbonate, dimethyl carbonate, and others that form the backbone of battery electrolytes. This trait supports consistent ionic conductivity and stable solid electrolyte interphase (SEI), traits every electric vehicle engineer knows by heart. Pure LiFSI rarely carries color or strong odor, another signal of chemical stability and cleanliness in a finished product.
Industries demanding high performance want detailed numbers before making decisions. Appearance speaks for itself—white powder, flakes, or crystals. Content purity determines reliability. Top-tier LiFSI boasts over 99% purity with less than 20 ppm water content, minimizing the risk of side reactions inside sensitive battery cells. The molecular formula—LiN(SO2F)2—defines its unique arrangement of lithium, nitrogen, sulfur, oxygen, and fluorine. Each atom plays a role in supporting high electrical conductivity and preventing unwanted breakdown reactions that shorten battery lifespan. Lithium itself makes up about 7-8% by mass in the finished salt, based on certificate of analysis checks.
Shipping and international trade require clear labeling. LiFSI falls under HS Code 2825.20, covering inorganic lithium compounds. This code unlocks global access, letting battery makers in Asia, Europe, and America source materials. Proper handling and documentation ensure safe delivery to gigafactories, large research centers, and specialty labs. By shipping under the correct HS Code, importers avoid regulatory headaches and customs delays. Countries set safety standards for each shipment, so suppliers take care to package LiFSI in moisture-tight drums, lined bags, or secure bottles to guard against accidental leaks or degradation, especially when large volumes cross borders.
Density counts for storage and design. LiFSI ranges from 1.45 to 1.55 g/cm3, falling neatly between heavier metal salts and lighter lithium carbonate. This density means it packs energy tightly while staying manageable for machine feeding or hand mixing. As flakes or powder, it flows smoothly, making volumetric dosing in automated battery slurry lines predictable and efficient. Handling needs a steady hand and a dry workspace—moisture reduces shelf life, so careful storage and desiccant use pay off. Whether poured by the kilogram or measured in lab beakers by the liter, users appreciate a material that resists caking and sticks with familiar storage practices. Sealed foil bags, solid plastic buckets, and double-sealed glass bottles keep the product dry and free from dust contamination.
Working with LiFSI means respecting its chemistry. As with many lithium salts, it poses harm if handled carelessly. Contact with eyes or the respiratory system can cause discomfort or injuries, so proper ventilation, protective gloves, and sealed goggles are standard. Clean workspaces with well-marked spill kits keep small mishaps from turning dangerous. Material Safety Data Sheets (MSDS) flag LiFSI as potentially harmful and hazardous, not because of wild reactivity but due to possible skin or mucous membrane irritation and the toxicity of lithium ions in high doses. Storage away from acids, moisture, and incompatible solvents is basic practice. Lithium handlers rely on strict labeling and robust training. Used responsibly, LiFSI brings value from research bench to production lines, without excessive risk for trained staff.
Every gram of LiFSI begins with high-purity lithium, fluorosulfonyl chloride, and nitrogenous bases—each with its supply-chain quirks and regulatory scrutiny. Growth in battery demand creates a tight global market for lithium chemicals. Producers refine their processes to recover solvents, reduce emissions, and recycle waste streams, keeping both costs and footprints lower. Transparent supply chains—ensuring responsible mining, fair wages, and reduced environmental impact—build trust between chemical companies and their clients. Innovations in production, such as closed-loop gas recovery and improved precipitation steps, cut down on dangerous byproducts and raise batch purity. Scaling up means investing in greener technology, capturing side products as usable materials, and documenting every step from mine to finished battery. Safer, less hazardous alternatives are under research, but for now, LiFSI forms the backbone of next-generation battery projects that hope to cut down on fires, run longer, and support a more electrified future.
