# Perspectives and Limitations of Tartaric Acid Diamides as Phase Change Materials for Sustainable Heat Applications

## TL;DR

This paper explores tartaric acid diamides as sustainable phase change materials for thermal energy storage at intermediate temperatures, offering improved melting points and enthalpy.

## Contribution

The study introduces tartaric acid diamides as a novel class of phase change materials with melting temperatures suitable for renewable energy storage.

## Key findings

- TA diamides exhibit melting temperatures between 130 and 190 °C, suitable for intermediate thermal applications.
- Melting enthalpies of TA diamides reach up to 173 J g−1, showing good energy storage potential.
- Characterization techniques reveal insights into the thermal behavior and limitations of TA-derived materials.

## Abstract

Phase change materials (PCMs) with melting temperatures in the intermediate range (100–220 °C) have recently been in high demand for applications in solar and wind renewable energy storage. Such materials can help advance thermal battery technologies, e.g. Carnot batteries, that can reduce the amount of fossil fuels used to generate electricity, contributing to substantial savings in CO2 emissions. Recently, polyol esters have been recognized as robust PCMs with high stability and high energy storage density (up to 221 J g−1), additionally meeting sustainability and circularity criteria, being sourced from inexpensive, biorenewable tartaric acid (TA), which provides H‐bonding, boosting the esters’ thermal properties. However, the melting points of TA esters, which are below 100 °C, limit their suitability for applications in the intermediate temperature range. In this study, TA diamides are explored as candidates for thermal energy storage with improved melting temperatures ranging from 130 to 190 °C and melting enthalpies up to 173 J g−1. With the aid of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and variable‐temperature Fourier‐transform infrared spectroscopy (FT‐IR), various perspectives and limitations of designing TA‐derived PCMs for sustainable heat use above 100 °C are investigated.

In this study, tartaric acid diamides are explored for thermal energy storage with melting temperatures ranging from 130 to 190 °C and melting enthalpies reaching 173 J g−1. With the aid of differential scanning calorimetry, thermogravimetric analysis, and variable‐temperature infrared spectroscopy, various perspectives and limitations of designing tartaric acid‐derived phase change materials for sustainable heat use above 100 °C are investigated.© 2025 WILEY‐VCH GmbH