Stretchable and self-healable double-network ionogel with strong adhesion and temperature tolerance for information encryption

•A high-performance double-network ionogel with interpenetrating physical/chemical cross-linked networks was constructed.•The ionogel exhibits good stretchability, excellent adhesion and wide operating temperature range.•Imidazole-modified carbon quantum dots are doped into the matrix to endow ionogel with tunable fluorescence performance.•The fluorescent ionogel has been successfully made into a double-layer device for effective information encryption.