Within this dataset, Plug Power holds all 19 ranked records, making it the sole assignee in the ranked field for this specific search on membrane crossover, reinforcement, and degradation. This does not mean Plug Power is the only company working on PEM electrolyzer membranes broadly — the search string is narrowly built around specific degradation mechanisms, so companies filing under different claim language may not appear here. Anyone using this for competitive tracking should treat it as a mechanism-specific slice rather than a full market map.

Filing peaked at 13 records in 2022 and has declined since, with the most recent tracked year showing a -100% year-on-year change for the leading assignee. Some of that recent drop is expected because publication typically lags actual filing by about 18 months, so the last one to two years will always look thinner than they eventually turn out to be. Even accounting for that lag, the multi-year shape from the 2022 midpoint reads flat to declining rather than growing.

The dominant classes in this dataset are B01D (separation processes, including filtration) and C25B (electrolytic production of compounds), each appearing on 73.7% of the 19 records. H01M, the fuel cell and battery class, appears on 52.6% of records, reflecting overlap between electrolyzer and fuel cell membrane technology. Polymer-processing claims under C08J are comparatively rare at 21.1%, indicating the membrane material chemistry itself is less densely claimed than the surrounding system architecture.

US20240344212A1, filed by Plug Power and published 2024-10-17, describes a method for forming a recombination layer using an ionomer with a nanocrystal catalyst dispersed inside it, intended to mitigate hydrogen crossover in proton exchange membranes. The claimed process covers providing an ionomer dispersion, introducing a charged catalyst compound, mixing it into the ionomer, reducing the catalyst to a metal state in place, and forming the resulting mixture into a recombination layer. Anyone designing a crossover-mitigation layer using an in-membrane metal nanocatalyst reduced directly within an ionomer matrix should review this filing's claim scope closely.

The clearest gap relative to the core separation and electrolysis classes is in polymer-processing and material-chemistry claims (C08J), which cover only 21.1% of the 19 records against 73.7% for B01D and C25B. Layered-structure reinforcement (B32B) at 26.3% is also comparatively open. Given that a single assignee holds the entire ranked field, sub-areas addressing differential-pressure sealing, fluoride-release monitoring, or ionomer blend formulations look under-claimed relative to the reaction and separation architecture that dominates current filings.