Spinel structure refers to a specific type of crystal arrangement found in some materials, including certain lithium-ion battery cathodes. The classic spinel mineral is MgAl₂O₄, but in batteries, the notable spinel is lithium manganese oxide, LiMn₂O₄, often just called “spinel” for short. In a spinel lattice, the oxygen anions form a cubic close-packed structure, and the cations occupy some of the interstitial sites in an orderly way, giving a specific three-dimensional framework. Spinel cathodes like LiMn₂O₄ have 3D lithium diffusion pathways, which can allow for high power (fast charging/discharging) since lithium can move through the structure relatively freely. They also tend to have good thermal stability and are potentially lower cost. However, spinel LMO has a moderate energy density and can suffer from capacity fading due to Mn dissolution (especially at higher temperatures or with certain electrolytes). Spinel structures are also found in other cathodes, like certain high-voltage LCO variants or lithium titanate (LTO) anodes, which have a spinel-like structure.
NOVONIX works with spinel materials, particularly in contexts like LMO cathodes or LTO anodes. They test LMO either alone or blended with other cathodes (like adding some LMO to NMC to lower cost). They investigate the fading mechanisms (like Mn dissolution from spinel LMO) by simulating extended cycles under warm conditions and analyzing the cell (maybe checking the deposition of Mn on anodes, which is a known issue). With their precise measurement, they can see improvements from additives that stabilize the spinel or coatings on LMO particles. If a client is developing a new spinel-based high-voltage cathode (there are spinels that operate above 4.7 V with other elements), NOVONIX would examine how it performs versus the normal spinel and what challenges appear (e.g., electrolyte oxidation at those high voltages). For LTO (a spinel-structured anode), which is zero-strain and very long-life, they’d test its coulombic efficiency and see virtually no lithium consumption per cycle, highlighting its great cycle life. By characterizing spinel cathodes and anodes, NOVONIX supports optimizing these structures’ use, whether it’s leveraging their power capability or mitigating their downsides (like the fade of LMO) with better electrolytes or cell designs.
