Bio-Based Poly(hydroxy urethane)s for Efficient Organic High-Power Energy Storage.

Fast, low-cost, and efficient energy storage technologies are urgently needed to balance the intermittence of sustainable energy sources. High-power capacitors using organic polymers offer a green and scalable answer. They require dielectrics with high permittivity () and breakdown strength (), which bio-based poly(hydroxy urethane)s (PHUs) can provide. PHUs combine high concentrations of hydroxyl and carbamate groups, thus enhancing their , and a highly tunable glass transition (), which dictates the regions of low dielectric losses. By reacting erythritol dicarbonate with bio-based diamines, fully bio-based PHUs were synthesized with ∼ 50 °C, > 8, > 400 MV·m, and low losses (tan δ < 0.03). This results in energy storage performance comparable with the flagship petrochemical materials (discharge energy density, > 6 J·cm) combined with a remarkably high discharge efficiency, with η = 85% at and up to 91% at 0.5 . These bio-based PHUs thus represent a highly promising route to green and sustainable energy storage.