However, some strong barriers can only be traversed with much stronger Electrograna. Perhaps offering Electro Sigils to the Sacred Sakura at the Grand Narukami Shrine will one day allow you to pass through all areas shut off by Thunder Barriers.

Some Thunder Barriers seal Thunderstones within them.
These fragments of raw, unbridled energy can be temporarily suppressed with Electrograna.
While a Thunderstone is suppressed, the Thunder Barrier around it is removed.