Carbon foam for next-generation electrochemical energy storage: advances, challenges, and outlook

The increasing global demand for clean and sustainable energy has accelerated the development of advanced electrochemical energy storage systems. A critical factor in improving the efficiency of such systems lies in optimizing electrode structures and components, including both active electrode materials and current collectors. This study explores carbon foam (CF) as a versatile carbon material that can serve either as a porous electrode or as a 3D current collector, owing to its superior physicochemical properties such as high porosity (∼97–99 %), excellent thermal and electrical conductivity, low density, and structural robustness. The primary objective is to review recent advances in the synthesis, characterization, and applications of CFs in supercapacitors, fuel cells, and redox flow batteries. This review employs comparative analysis of literature data and material characterization insights to evaluate CFs’ structural advantages (e.g., hierarchical porosity, tunable pore sizes, and graphitization levels) and their impact on electrochemical performance. This tunability is typically achieved by varying precursor type, foaming agent concentration, and carbonization/graphitization conditions, which collectively determine pore size distribution and connectivity. Results show that the integration of CFs can enhance conductivity (up to 150 S/cm with CNT decoration), increase areal capacity (4.3 ${mAhcm}^{-2}),$ and improve energy and power densities significantly. The novelty of this work lies in highlighting CF as more than just a structural support it functions as a multifunctional component that significantly improves both electrical conductivity and mass transport. By bridging these two critical performance factors, this review offers valuable insights for the development of next-generation porous electrodes. However, carbon foams also face practical constraints brittle frameworks, energy-intensive high-temperature processing, and electrolyte-compatibility issues in aqueous media that require targeted materials and process innovations. These findings open up promising opportunities for applications in flexible electronics, hybrid energy storage devices, and high-efficiency electrochemical systems.