Nature Communications, Published online: 12 June 2026; doi:10.1038/s41467-026-73829-z Through multiscale structural engineering, this work achieves a high recoverable energy density of 14.39 J/cm3 (one of the highest reported for bulk tetragonal tungsten bronze ceramics) and an efficiency of 87.69% in Ba2LaTi2Nb3O15-based ceramics.