A multisite super-crosslinked sulfur-heterocyclic polymer cathode for high-voltage and low-temperature...

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 (<1.5 V for almost all AOBs). Tailoring the linking patterns of polymers to increase active sites can maximize redox activity to 12-electron-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's excellent low-temperature durability, with almost 100% capacity retention after 12 000 cycles at -20°C.