# Barium calcium zirconium titanate thin film-based capacitive thermoelectric converter for low-grade waste heat

## TL;DR

This paper introduces a new capacitive thermoelectric device using barium calcium zirconium titanate thin films to convert low-grade heat into electricity.

## Contribution

The novelty lies in using specific barium calcium zirconium titanate thin films to improve the efficiency of capacitive thermoelectric converters.

## Key findings

- The device achieved power outputs of 0.06 mW to 0.3 mW with temperature differences of 5–20°C.
- It performed under a dynamic workload of an Intel E5-2630 microprocessor.
- The material shows potential for low-grade waste heat conversion.

## Abstract

A capacitive thermoelectric device can harvest thermal energy and convert it to electrical energy by employing a temperature-dependent dielectric material whose permittivity sharply changes with temperature. Electricity can be generated by fluctuating the temperature of the capacitor. Currently, capacitive thermoelectric devices are not broadly used, which can be attributed to the low efficiency of the existing solutions, the lack of dielectric materials with suitable temperature non-linearity of the dielectric permittivity, and the complexity of modulating heat flux on the dielectric material. Here, we propose a device based on (Ba0.85Ca0.15)(Ti0.92Zr0.08)O3 and (Ba0.73Ca0.27)(Ti0.98Zr0.02)O3 thin films. It demonstrates power outputs of 0.06 mW to 0.3 mW across ΔT = 5–20 °C at 15 V bias, and a dynamic workload of an Intel E5-2630 microprocessor. These results highlight the potential of barium calcium zirconium titanate thin films to be used for a capacitive thermoelectric converter.