Combining Janus Separator and Organic Cathode for Dendrite‐Free and High‐Performance Na‐Organic Batteries

Abstract The growth of Na‐dendrites and the dissolution of organic cathodes are two major challenges that hinder the development of sodium‐organic batteries (SOBs). Herein, a multifunctional Janus separator (h‐BN@PP@C) by using an interfacial engineering strategy, is proposed to tackle the issues of SOBs. The carbon layer facing the organic cathode serves as a barrier to capture dissolved organic materials and enhance their utilization. Meanwhile, the h‐BN layer facing the Na anode possesses high thermal conductivity and mechanical strength, which mitigates the occurrence of localized‐temperature “hot spots” and promotes the formation of a NaF‐enriched SEI, thereby suppressing dendrite growth. Consequently, the Janus separator enables a stable Na plating/stripping cycling for 1000 h at 3 mA cm −2 . Equipped with the Janus separator, organic cathodes including dibenzo[b,i]thianthrene‐5,7,12,14‐tetraone (DTT), pentacene‐5,7,12,14‐tetrone and Calix[4]quinone cathodes demonstrate high capacity and remarkable cycling performance. In particular, the DTT exhibits a bipolar co‐reaction storage mechanism and achieves an ultrahigh capacity (≈342.6 mAh g −1 ), long‐term cycling stability (capacity decay rate of 0.15% per cycle over 550 cycles at 500 mA g −1 ) and fast kinetics (1000 mA g −1 ≈2.8 C). This study offers a straightforward, effective, and promising solution to address the challenges in SOBs.