It refers to claims that address the boundary between electrode and electrolyte inside a hybrid, asymmetric or lithium-ion capacitor — covering things like the solid-electrolyte interphase (SEI), interfacial impedance, and wettability between the electrode surface and the electrolyte. In this dataset those claims are almost always paired with core capacitor structure classes (H01G) and often overlap with battery-anode classes (H01M), because prelithiation and composite-anode techniques borrowed from lithium-ion battery work are common ways to engineer that interface. The 52 matched families sit specifically at that intersection rather than in general capacitor design.

The trend in this dataset rises from one filing in 2017 to a peak of 11 in 2020, then falls to 3 by the 2022 midpoint. That pattern can reflect a genuine slowdown in new filings, a shift of R&D effort into adjacent chemistries not captured by this search string, or simply the corpus's own publication lag understating the last one to two years of activity. Treat the 2020 peak as real and the most recent years as provisional until later publication catches up.

The assignee momentum data in this dataset shows several previously active filers — including Komatsu Ltd. (Komatsu) and Asahi Kasei Corporation (Asahi Kasei) — recording zero filings in the latest year, a -100% year-on-year change for both. That does not necessarily mean they have exited the field; it may reflect the publication lag or a pause between filing cycles. A practitioner should check live filing activity directly rather than relying solely on the most recent year in a historical corpus.

Not on its own. Citation counts inside a searched patent corpus favour older filings simply because they have had more years to accumulate citations, so the most-cited records here — such as CN105513828A and US9385397B2, each cited 20 times — are signals of past influence on subsequent filings, not proof that the underlying technology is still the commercial standard. Newer, less-cited filings, like composite niobium-oxide anode claims, may be more relevant to current designs even though their citation counts are lower.

Based on the IPC composition in this dataset, the core capacitor and battery-anode classes (H01G, H01M) are heavily claimed, while adjacent classes — layered laminate structures (B32B), nanotechnology-specific treatments (B82Y), and catalytic/chemical interface treatments (B01J) — each carry only one or two records. That thinness suggests those adjacent branches are where a first claim has the most room to stand without colliding with the dense prior art in the core classes. Co-assignee collaboration is also rare here, with only two pairs identified, so joint-filing precedent is not a strong constraint either.