A solid-state supercapacitor replaces the liquid or gel electrolyte found in conventional supercapacitors with a solid or solid-polymer electrolyte, which removes the risk of leakage and generally improves mechanical flexibility. This matters for wearable and flexible electronics, where a liquid electrolyte cell cannot be bent repeatedly without failing. The tradeoff documented across this patent corpus is that the electrode-electrolyte interface in solid systems is harder to maintain over repeated cycling and bending, which is exactly the reliability problem this search string targets. Patent filings in this space concentrate heavily in the H01G capacitor classification, with supporting art in battery and inorganic-compound chemistry.

Filing activity in this dataset peaked at 26 records in 2018 and has fallen through the 2022 midpoint of 7 down to 4 in the partial 2026 year. Part of that decline is a publication-lag artifact: patents filed in 2025 and 2026 typically have not yet published, so the most recent one or two years always understate real activity. But the multi-year downward trend predating that lag window is more likely a sign that foundational claim territory in graphene-electrode and basic interfacial-engineering approaches was staked early, pushing newer filers toward narrower or adjacent claims rather than the core architecture.

The dataset shows a research-university-plus-industry pairing as the strongest co-assignee relationship, sharing ten families together, which indicates a concentrated joint claim position around a specific technical approach rather than a single dominant corporate holder. Beyond that pairing, recent-year momentum across the named assignees in this corpus shows zero new filings in the latest year for each, suggesting the most active historical filers have slowed or shifted their filing elsewhere rather than continuing to build on this specific claim territory. This is consistent with a field where core claims were filed years ago and are now being licensed or cited rather than extended.

Interfacial stability refers to maintaining low resistance and consistent capacitance at the boundary between the solid electrolyte and the electrode material through repeated charge-discharge cycles or mechanical bending, which is the specific failure mode named in this search string. It is hard to protect narrowly because most filings claim it at the device or fabrication-method level, as seen in the representative record US20160055983A1, rather than through a dedicated coating or interlayer composition. That leaves the coatings-classification branch of this corpus (C09D, 10 records) relatively thin compared to the 117-record capacitor core, which is a specific area for a first claim on a distinct interfacial coating chemistry.

The classification spread in this corpus points to ceramics-based solid electrolytes (C04B, 7 records), interfacial coatings (C09D, 10 records) and semiconductor-integrated designs (H01L, 8 records) as the thinnest branches relative to the 117-record H01G capacitor core. These are exactly the areas most relevant to the bending-durability and interfacial-stability problems named in the search criteria, yet they carry the fewest filings, which suggests the field has argued these failure modes mostly through device-level claims rather than dedicated composition or coating claims. A first claim tied to a specific coating chemistry, thickness and a quantified cycle-retention metric would sit in territory that is comparatively open today.