Carnot cycle

Electrical engineering

Physics

Pyroelectricity

Energy (signal processing)

Common emitter

Capacitor

Photovoltaics

Engineering physics

Energy harvesting

Thermal energy

Thermophotovoltaic

Engineering

Dielectric

Voltage

Materials science

Electricity

Photovoltaic system

Quantum mechanics

Optoelectronics

Ferroelectricity

Thermodynamics

Nature

Coming up with sustainable sources of electricity is one of the grand challenges of this century. The research field of materials for energy harvesting stems from this motivation, including thermoelectrics 1 , photovoltaics 2 and thermophotovoltaics 3 . Pyroelectric materials, converting temperature periodic variations in electricity, have been considered as sensors 4 and energy harvesters 5–7 , although we lack materials and devices able to harvest in the joule range. Here we develop a macroscopic thermal energy harvester made of 42 g of lead scandium tantalate in the form of multilayer capacitors that produces 11.2 J of electricity per thermodynamic cycle. Each pyroelectric module can generate up to 4.43 J cm −3 of electric energy density per cycle. We also show that two of these modules weighing 0.3 g are sufficient to sustainably supply an autonomous energy harvester embedding microcontrollers and temperature sensors. Finally, we show that for a 10 K temperature span these multilayer capacitors can reach 40% of Carnot efficiency. These performances stem from (1) a ferroelectric phase transition enabling large efficiency, (2) low leakage current preventing losses and (3) high breakdown voltage. These macroscopic, scalable and highly efficient pyroelectric energy harvesters enable the reconsideration of the production of electricity from heat.

Large harvested energy with non-linear pyroelectric modules