Effect of the micro‐, meso‐ and macropores on the electrochemical performance of supercapacitors: A review

The scientific community is actively testing new materials to enhance the electrochemical properties of supercapacitors (SCs) and the porous nanomaterials/composites have emerged as promising candidates for such purposes. In this review, we summarize the most recent strategies to enhance the capacitance and cycling stability of electrode materials/SCs using micro-, meso- and macroporous structures. We described the morphology and surface properties of the porous nanomaterials/composites (containing or not carbon materials) published in the literature. Later, we explained how the parameters of pore size, pore-volume, surface area, orientation and morphology of the nanomaterials affect the electrochemical performance of the SCs. The type of pore (micro-, meso- and macropore) or the presence of various types of pores (meso-/micro-, macro-/meso-, etc) not only increased/decreased the capacitance of the materials/devices but also was critical to determine which mechanism (electric double layer or redox) was dominant for the charge storage. This review is useful to understand the main phenomena that affect the performance of SCs based on porous materials as well as to design new types of porous nanostructures with new physical and chemical properties, which in turn, would improve the lifetime and the charge storage capabilities of SCs.