Design and manufacturing of a microcalorimeter for measuring heat flows in electrochemical reactions to milli-Kelvin precision

Abstract

Due to their high energy density, lithium-air batteries have tremendous potential for application to batteries for electric vehicles. While significant efforts have been made in understanding the material origins of electrochemical performance under discharging and charging conditions, there is still very limited understanding of the thermodynamics and thermal science, including heat transfer, of such reactions. Several methods and procedures that have been previously used to deduce entropy profiles in batteries are examined. One such microcalorimetric device allows for measurements of heat flows in electrochemical reactions to milli-Kelvin precision. This device has not previously been applied to gas-to-solid reactions. Next, an explanation of the design and manufacture of a device adapted to measure heat flows in solid-togas electrochemical reactions is explained. The high sensitivity of the measurements resulted in high noise levels. This paper also explains the main methods used to address and reduce this level of noise.