Volume 44: Energy Transitions toward Carbon Neutrality: Part VII

The energy storage/release density and net energy density of the electrochemical Brayton cycle: A thermodynamic derivation Ruihua Chen, Weicong Xu, Shuai Deng, Ruikai Zhao, Li Zhao

Abstract

The power density and thermal efficiency of the electrochemical Brayton cycle (EBC) have been addressed through the conservation of energy. However, it remains a gap to determine the energy density of charging and discharging processes, a crucial aspect tied to energy storage/release density in EBC systems with integrated energy storage. This study derives the energy storage/release density and net energy density of the ideal EBC system, confirming key parameters including the change in state of charge ΔSOC and the dimensionless figure of merit αqv/cv (α: temperature coefficient, qv: specific charge, cv: specific heat) are confirmed. The theoretical energy storage/ release density approximates 10 W h L-1, and the net energy density is expected to reach 1.0 W h L-1. This study provides a valuable framework for assessing the energy storage performance of EBC systems.

Keywords energy storage, energy density, electrochemical Brayton cycle, thermodynamic cycle, electrochemical heat engine, flow battery