A review of unitized regenerative fuel cell stack: Material, design and research achievements

•An overview on the latest developments of PEM-URFC stack design has been demonstrated.•Most recent researches on developing a new method to decrease the cost of URFC stack have been recorded.•Clarify the main constituents of URFC stack design based on the performance and electrochemical behaviors.•Illustrate the suitable performance and electrochemical behaviors regarding on latest URFC stack design and materials.

The stack design of a unitized regenerative fuel cell (URFC) can modify the structure of cells that can be used as storage and energy regenerator aside from cells that use other sources such as solar or wind energy. A reversible unitized polymer electrolyte membrane fuel cell (PEMFC) contains a dual-functional single cell that is less expensive and has enhanced performance. The use of URFCs on hydrogen and oxygen is preferred because it is highly efficient, environmentally friendly, and uses power generators. The stack, then, must be made affordable or accessible. The expenses of URFC stack must be reduced by improving its design, materials, and performance. This study referred to recent studies on developing a method to cut the expenses of the URFC stack. The study also aims to determine its main constituents and to look further into its design by observing its performance and electrochemical behaviors. It also presents the issues that are currently encountered in this field.