In addition to the electronic conductivity, rate performance can be enhanced by significantly improving the ionic conductivity through chemical design. The simplest approach to modulating the ionic conductivity is to modify the size and arrangement of the pores, as this can facilitate ion diffusion. In general, COFs with small pores may present diffusion problems at high rates, especially for those metal ions and counterions with large ionic radius. For example, HATN-AQ-COF (pore size = 3.8 nm) shows a higher active sites utilisation efficiency (63%) at high current density (10 C) than that of BQ1-COF (pore size = 1.4 m, active site utilisation of 22% at 10 C) when explored as cathode materials for Li-ion batteries. This reveals that the design of mesoporous COFs (pore size = 2-5 nm) with welldefined channels may be key to improving ion diffusion. The design of hierarchical COFs with the presence of both meso-and micropores has also proven to be efficient for simultaneous ion and electron transport. The interlayer distance can also be modulated to improve the ionic conductivity. In general, COFs present stacked layers that often hinder the ion transport during electrochemical processes, so larger interlayer distances can favour better ion diffusion, higher utilisation of the redoxactive sites, and higher rate performance. This approach was explored in a redox-active piperazine-terephthaldehyde COF based on nonplanar linkages exhibiting a chair-shaped conformation, resulting in a large interlayer distance of 6.2 Å. This interlayer distance facilitated ion transport, improving the electrochemical performance even at high rates (207 mAh g -1 at 5 C) when used as anode in LIBs. However, this strategy is in contrast to a better interlayer overlap which is favourable for a high out-of-plane electronic conductivity. Other strategies to increase the ionic conductivity in COFs are based on the preparation of cationic frameworks, the incorporation of sulfonate groups, or post-functionalisation of the channels by anchoring, for example, oligo(ethylene oxide) moieties. However, these strategies significantly reduce the specific capacity and are therefore more focused on solid electrolytes applications.