The dataset shows filings peaking at 13 in 2017 and falling to 5 by 2022, with none yet recorded in the most recent year. This pattern typically reflects a technology area where the core chemistry — doped spinel structures and surface coatings — has already been claimed by early filers, leaving later entrants to compete for narrower formulation variants. Publication lag of roughly 18 months means the very latest year is always undercounted, but the multi-year decline predates that effect and looks structural rather than temporary.

Valence Technology shows the strongest co-assignee filing pattern in this corpus, paired with named inventor Jeremy Barker across six co-filings, alongside academic-national lab collaborations such as Argonne National Laboratory with Northwestern University. None of the assignees tracked in recent-year momentum data, including LG Chem and Argonne-linked filers, show any filings in the latest year, suggesting the competitive core was established some years ago rather than being actively contested now.

US6692665B2, assigned to Mitsubishi Chemical, claims a lithium manganese oxide spinel defined by a specific compositional formula, a doping metal element, and a bounded ratio of NMR peak intensities tied to high-temperature cycling performance. It does not block all LMO cathode work — it blocks formulations that fall within its specific formula and NMR-ratio bounds. Work outside those compositional bounds, or using different characterization criteria for cycling stability, generally sits outside its claim scope, though a formal freedom-to-operate review is needed before relying on that distinction.

The IPC composition shows nearly all 526 families concentrated in H01M and C01G classifications covering the core battery electrode material, while application-adjacent classes like B60L (electric vehicle propulsion) and H02J (grid systems) carry a small fraction of filings. That imbalance suggests thinner claim density in areas like nanostructured LMO coatings, gradient-doped spinel surfaces, and LMO-solid electrolyte interface work — branches that touch the core chemistry but have not been as heavily claimed.

High filing density in the core spinel and surface-coating claims means that space is occupied, not that the underlying chemistry is exhausted commercially — LMO remains in active use for cost-sensitive and safety-focused battery applications. The more productive path based on this landscape is to target the thinner-claimed adjacent branches, such as coating nanostructure or electrolyte interface compatibility, rather than re-filing on the well-covered core formula and doping claims.