Integrated intercalation-based and interfacial sodium storage in graphene-wrapped porous Li4Ti5O12 nanofibers composite aerogel
Sodium storage in both solid-liquid and solid-solid interfaces is expected to extend the horizon of sodium-ion batteries, leading to a new strategy for developing high-performance energy-storage materials. Here, a novel composite aerogel with porous Li4Ti5O12 (PLTO) nanofibers confined in a highly conductive 3D-interconnected graphene framework (G-PLTO) is designed and fabricated for Na storage. A high capacity of 195 mA h g-1 at 0.2 C and super-long cycle life up to 12 000 cycles are attained. Electrochemical analysis shows that the intercalation-based and interfacial Na storage behaviors take effect simultaneously in the G-PLTO composite aerogel. An integrated Na storage mechanism is proposed. This study ascribes the excellent performance to the unique structure, which not only offers short pathways for Na+ diffusion and conductive networks for electron transport, but also guarantees plenty of PLTO-electrolyte and PLTO-graphene interfacial sites for Na+ adsorption.