Graphene Aerogel Armed 3D Ordered Mesoporous Carbon as Versatile Anode Platforms for Sodium‐Ion Storage Devices

The rise of Na‐storage devices has put forward higher requirements for Na‐storage anode materials with large capacity, long service life, and fast rate capability. Mesoporous carbons, either as active materials or as hosts for guest active nanoparticles, are considered as promising electrode materials. However, addressing the issues of their short lifespan resulting from volume variation and the low coulombic efficiency caused by large surface area via a facile porous structure design still remains a challenge. Herein, a versatile phosphorus‐doped mesoporous carbon (PMC) armed is developed by graphene aerogel (GA) (GA@PMC) for hosting Na‐storage active nanoparticles. As a case study, FeSe2 nanoparticles are selectively supported onto this GA@PMC matrix, creating the FeSe2/GA@PMC composite. When employed in typical Na‐storage devices, such as Na‐ion batteries, Na‐ion hybrid capacitors, and Na‐ion based dual‐ion batteries, the FeSe2/GA@PMC electrode consistently demonstrates superior electrochemical performance. In such GA@PMC, the conformal GA can improve the entire conductivity while decreasing the specific surface area that is directly contacting with electrolyte. The interconnected macroporous structure can not only promote the diffusion of Na+ but also buffers the volume change of the guest active nanoparticles. This bespoke carbon platform synergistically endows the electrode material with enhanced rate capability, cyclic stability, and coulombic efficiency, which are being expected in advanced Na‐storage devices. FeSe2 nanoparticles are successfully encapsulated in phosphorus‐doped mesoporous carbon (PMC) armed by graphene aerogel (GA) (GA@PMC) to prepare a FeSe2/GA@PMC composite. Compared with bare PMC, the GA@PMC composite can provide enhanced electroconductivity, rapid Na+/electrolyte diffusion channels, decreased surface areas, and more integrated and stable structure. As expect, FeSe2/GA@PMC electrode demonstrates superior electrochemical performance in Na‐ion based energy storage devices.