A record is included only if it combines lithium ion capacitor, hybrid capacitor, or prelithiated anode terminology with a specific technical concern such as prelithiation method, voltage window management, high-temperature cycling, cell balancing, energy-power tradeoff, or leakage current. This excludes generic supercapacitor filings that never touch a lithium-hybrid architecture and generic lithium-ion battery filings that never engage a capacitor-style tradeoff. The result is 1,048 records that are specifically about solving the hybrid device’s characteristic engineering problems, not just mentioning the term in passing.

The ranked list covers 100 assignees, with the leader holding 95 records, fifth place at 45, and tenth place at 24 — a steep drop-off that signals one dominant filer well ahead of a fragmented field. The top five combined account for 29.0% of all 1,048 records, and the top ten for 41.7%. Beyond that, filing activity spreads thinly across the remaining ranked companies, many of which appear with only a handful of records each.

Filings rose from 77 in 2017 to a peak of 97 in 2020, then declined to 47 by 2024, a 35% drop over that three-year span — the most recent period that can be read reliably. Counts for 2025 and 2026 are still incomplete because publication typically lags actual filing by around 18 months, so it is too early to call the current trajectory a continued decline. The honest read is that activity has cooled from a 2020 peak but the last two years of data are not yet a fair test of current interest.