Filing activity concentrates around a cluster of Chinese battery-materials and recycling-linked assignees, including Brunp-affiliated entities and Hubei Wanrun New Energy, alongside lower but historically present filing from Korean and Japanese cell makers such as Samsung SDI and LG Energy Solution. The recycling-linked cluster stands out for co-filing patterns, with the strongest co-assignee pair in the dataset (71 shared filings) linking two Brunp affiliates. No single assignee holds a dominant share of the 2,656 tracked families; the field is a long tail beneath a handful of moderately active filers.

Filing rose from 74 families in 2017 to a peak of 327 in 2025, but the growth was uneven rather than steady, with 2022 already at 246 — close to the eventual peak years earlier. Recent-year momentum data shows every actively tracked assignee filing less than the year before, with declines ranging from -25% to -89%. That pattern reads as a plateau and early pullback rather than continued expansion, though the partial 2026 count is understated due to normal publication lag.

This Hubei Wanrun filing, published 2024-11-28, claims a lithium iron phosphate positive electrode material with high tap density, made by grinding and spraying a mixed iron-lithium-carbon-dopant solution into a precursor powder and sintering it at high temperature. The claimed advantages are high specific capacity alongside the tap-density improvement, achieved through what the filing describes as a simpler, more controllable and more productive process than prior approaches. Anyone developing a tap-density-focused LFP synthesis route should review this filing's process steps closely before committing to a similar grind-and-spray precursor method.

IPC composition data shows B82Y (nanotechnology-framed composite coatings), C01D (alkali-metal compound co-doping), B01J (catalysis-adjacent processing) and B22F (powder-metallurgy precursor routes) carry far fewer families than the dominant H01M and C01B classifications. These thinner branches are candidates for new filings with a clearer path around existing claims, though thinner filing density does not by itself indicate the technology is easier to commercialize. Practitioners should still check the most-cited records in adjacent classifications before assuming a route is open.

Of the tracked filings by receiving office, 1,588 went through China, compared with 353 for the EPO, 312 for the US, and only 105 through the WIPO PCT route. This reflects both the concentration of LFP materials manufacturing in China and a filing strategy where many applicants secure domestic protection first and pursue international filing more selectively. A filing that only appears in the China office may still be extended abroad later within the PCT priority window, so absence from EPO or US data does not guarantee freedom-to-operate outside China.