Structure and properties of clay ceramics for thermal energy storage

Pierre Marie Nigay, Ange Nzihou, Claire Emily White, Winston O. Soboyejo

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


In this paper, the structure-property relationships of a clay ceramic with organic additives (biomass and biochar) are investigated to develop an alternative material for thermal energy storage. The firing transformations were elucidated using X-ray pair distribution function analysis, differential scanning calorimetry, and scanning electron microscopy. It was found that the biomass increased the porosity, which resulted in a decrease of the specific heat capacity. On the other hand, the biochar remained in the clay ceramic without any interaction with the clay matrix up to 950°C. The specific heat capacity of the clay ceramic increased from 1.20 to 1.49 kJ/kg·K for a 30 wt% addition of biochar. The clay ceramic with a 30 wt% addition of biochar also conserved a high flexural strength of 11.1 MPa compared to that of the clay ceramic without organic additives (i.e., 18.9 MPa). Furthermore, the flexural strength only decreased by 23% after 100 thermal cycles. The crack growth associated with the thermal fatigue was limited by crack bridging and crack trapping. Hence, the current results suggest that clay/biochar ceramics can be as efficient as molten salts in thermal energy storage with the added benefit of an ease of use in the physical form of bricks.

Original languageEnglish (US)
Pages (from-to)4748-4759
Number of pages12
JournalJournal of the American Ceramic Society
Issue number10
StatePublished - Oct 2017

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry


  • R-curve
  • energy conversion
  • fatigue
  • phase transformations
  • thermal properties


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