In-situ induced self-solidification and activation of ultra-high energy density organic cathode

The strong dissolution and short conductivity of organic molecular cathodes restrict their rapid development. To overcome these bottlenecks, it is imperative to develop an effective polymerization method while maintaining their high capacities. To overcome these issues, the method of in situ electrochemical polymerization has been developed that the terminal-acetylene coupling occurs at high operating voltage without Cu elements. Such electrochemical coupling leads to the polymerization of organic molecular cathodes and thus in situ self-solidified at the current collector. This is a very effective method to show that the kinetic performance and the long-term stability of the molecular cathode are greatly improved. What is significant is that this process successfully activates the diyne bonds, leading to the capacity to store anions at high operating platform for the first time was observed, which more than compensates for the reduction in specific capacity. Utilization of the general approach, the assembly engineering of organic battery is unprecedentedly simplified, and the cathode based on 2,7-diethylnylpyrene-4,5,9,10-tetraone delivers an ultrahigh capacity of 411 mAh/g with a robust retention in 1000 cycles. The energy density is raised up to 955 Wh/kg. Our results demonstrate that such a method has broad application prospects in organic batteries with high energy density.