Hierarchical Porous Nitrogen‐Doped Spray‐Dried Graphene for High Performance Capacitive Deionization

Graphene foam materials have attracted particular attention for capacitive deionization (CDI) applications due to their robust conductive framework and open three‐dimensional porous structures. However, their salt adsorption capacities (SACs) are limited by the bland macropores and poor compatibility with aqueous environments. Herein, hierarchical porous nitrogen‐doped spray‐dried graphene (N‐SDG) is prepared through a spray‐drying method followed by low‐temperature nitrogen doping. The resulting material exhibits hierarchical porosity and a nitrogen‐rich carbon framework which demonstrates an improved SAC of 19.6 mg g −1 in 500 mg L −1 NaCl solution, amongst the highest reported for graphene‐based CDI materials. The method herein demonstrates a commercially attractive approach for the production of N‐doped porous graphene material for CDI applications. These findings are expected to underpin new developments in low‐cost graphene‐based materials for a range of applications.