Optimized Cathode for High-Energy Sodium-Ion Based Dual-Ion Full Battery with Fast Kinetics

The most used systems based on the graphite-based cathode show unsatisfactory performance in dual-ion batteries. Developing new type cathode materials with high capacity for new type anions storage is an effective way to improve the total performance of dual-ion batteries. Herein, a protonated polyaniline (P-PANI) cathode is prepared to realize efficient and stable storage of ClO4-, and a high reversible capacity of 143 mAh g(-1) at 0.2 A g(-1) after 200 cycles can be obtained, which is competitive compared with common graphite cathodes. In addition, the highly reversible coordination storage mechanism between ClO4- and P-PANI cathode is indicated, rather than the labored intercalation reactions between PF6- and graphite. Subsequently, a full cell (P-PANI//N-PDHC) fabricated with a P-PANI cathode and hard carbon anode (N-PDHC) can deliver a high energy density of 284 Wh kg(-1) for 2000 cycles at 2 A g(-1), and the relevant pouch-type full cell can easily power a smartphone. In general, this work may promote the exploitation of sodium-based dual-ion batteries in practical application.