This link was posted by a reader on the Journal of Nuclear Physics today. A team from MIT has reported achieving thermovoltaic (heat to electricity) conversion of 40 per cent using graphite cells.
The article is published in Nature and is available here:
The conversion was achieved at temperatures in the 1900-2400 Celsius range using a cell of 10 x 10 mm in size.
“Reaching 40% efficiency with TPVs is notable from the standpoint that it now renders TPV as a heat engine technology that can compete with turbines. An efficiency of 40% is already greater than the average turbine-based heat engine efficiency in the United States”
The article proposes that such cells could be used as a grid-storage battery that takes in excess electricity (when not needed by the grid), stores it as heat, then converts it back to electricity on demand. The article states that projected capital cost per energy unit is less than $20 per kWh which the authors believe would be cost competitive with fossil fuels if the heat source was from renewable energy.
In a news release from MIT (https://news.mit.edu/2022/thermal-heat-engine-0413), Professor Asegun Henry states: ““One of the advantages of solid-state energy converters are that they can operate at higher temperatures with lower maintenance costs because they have no moving parts, they just sit there and reliably generate electricity.”