A multisite super-crosslinked sulfur-heterocyclic polymer cathode for high-voltage and low-temperature aluminum-organic batteries

Abstract Simultaneously attaining high energy density and long cycling life remains a critical challenge for aluminum-organic batteries (AOBs) due to low operating voltage, limited active sites, and unstable coordination structure of organic cathodes. Herein, we design a multisite super-crosslinked sulfur-heterocyclic polymer cathode. The electronegative sulfur heterocycles can significantly weaken the electron-donating effect, promoting the operating voltage to 2.0 V (average ∼1.7 V), which is a breakthrough for AOBs (almost all AOBs < 1.5 V). Tailoring the linking patterns of polymers to increase active sites can maximize redox activity to 12-electrons-transfer, contributing to a high capacity of 150 mAh g−1. The designed organic cathode achieves 255 Wh kg−1 energy density, breaking the upper limit of conventional graphite cathodes (∼200 Wh kg−1). Notably, the weak coordination interaction between C‒S+‒C radicals and AlCl4− carriers ensures structural stability, enabling the battery excellent low-temperature durability, with almost 100% capacity retention after 12 000 cycles at − 20°C.