Na4MnCr(PO4)3 with a Dual Conductive Network for Sodium‐Ion Batteries

Abstract NASICON (NAtrium Super Ionic CONductor)‐structured Na 4 MnCr(PO 4 ) 3 has attracted attention as a promising cathode for sodium‐ion batteries due to its high operating voltage and specific capacity contributed by multielectron reactions. Unfortunately, its intrinsic low electronic conductivity significantly hinders the release of specific capacity and rate capability, preventing its practical application. Herein, a carbon layer with dual conductive networks connected by chain‐like Ketjen black (KB) is built on the surface of Na 4 MnCr(PO 4 ) 3 material. This novel Na 4 MnCr(PO 4 ) 3 /C@KB composite material exhibits improved rate capability of 61.2 mAh g −1 at 2 C compared to 19.5 mAh g −1 of Na 4 MnCr(PO 4 ) 3 /C and high reversible capacity of 88.0 mAh g −1 at 1 C with 73% capacity retention after 100 cycles. The enhanced electrochemical performance can be ascribed to an increase of electronic conductivity enabled by the dual conductive 3D network construction and an adequate infiltration of electrolyte by substantial pores existence in carbon layer. A promising dual conductive network design strategy is demonstrated here for improving the performance of NASICON‐structured cathodes.