Seed strategy synthesis of porous NASICON structured NaTi2(PO4)3/carbon aerogel nanocomposites for high-performance hybrid capacitive deionization

The limited capacity of conventional carbon electrode materials hinders the practical application of capacitive deionization (CDI). Hence, it is imperative to develop electrode materials with high sodium ion adsorption and reliable stability to facilitate the construction of hybrid CDI (HCDI) systems. Notably, NaTi2(PO4)3 (NTP) has received significant attention due to its high capacity and rapid transportation ability of sodium ions. However, the poor electrical conductivity and limited electrolyte contact area of NTP have prevented further improvement in its deionization capacity. Herein, we report a seed strategy to synthesize NTP/carbon aerogel (CA). P25 was used as a seed crystal to prepare TiO2/CA via the sol-gel method and supercritical CO2 drying. NTP/CA was then obtained from TiO2/CA by hydrothermal synthesis and calcination. This strategy preserved the rational network skeleton of CA and endowed NTP/CA with a high specific surface area of 420 m2/g. The enhanced electrical conductivity provided by CA yielded a remarkable salt adsorption capacity of 43.3 mg/g in a 500 mg/L NaCl solution and a stable cycle desalination capability. This work provides a new perspective for constructing threedimensional, highly efficient and stable HCDI electrode materials.