A Novel Non‐centrosymmetric Biocrystal With Hydration‐Enabled Symmetry Breaking and High Piezoelectricity

ABSTRACT Piezoelectric biocrystals offer transformative potential for bio‐integrated electronics in healthcare and regenerative medicine due to their intrinsic biocompatibility and biodegradability. However, their practical use has been significantly limited by weak electromechanical performance, with most exhibiting zero or low d 33 coefficients <10 pm V −1 . Here, we report a novel non‐centrosymmetric biocrystal, triglycine dihydrate (GGG‐DH), formed through the co‐assembly of natural triglycine peptides and water molecules. The incorporation of lattice water disrupts the centrosymmetric packing of pristine triglycine, yielding highly oriented microwires with a polar crystal structure ( Pca2 1 ). This peptide hydrate crystal exhibits robust thermal stability up to 50°C, strong non‐linear optical properties, and a high piezoelectricity with d 33 ≈ 20 pm V −1 (theoretically predicted as 22.13 pm V −1 ), comparable to that of commercial piezoelectric polymers such as polyvinylidene fluoride. Leveraging its biocompatibility, biodegradability, and processing compatibility with printing approaches, we further fabricated transient electromechanical devices for biomechanical energy harvesting and sensing. Our work presents hydration‐enabled symmetry breaking as a potential strategy for designing high‐performance electromechanical biomaterials and establishes the GGG‐DH biocrystal as an ideal material platform for next‐generation transient bioelectronics.