H. Dai#, Y. Chen#, Y. Gao#, L. Gong#, K. Fan, J. Zou, X. Wang, C. Zhang, M. Fu, G. Zhang, Y. Cao, C. Wang*, Constructing Structural Isomers to Reveal and Enhance Lithium Storage in a Conducting Polymer. Adv. Energy Mater. 2024, DOI: 10.1002/aenm.202304210.

原文链接：https://doi.org/10.1002/aenm.202304210

Abstract: Organic electrodes have gained great interest for batteries. Conducting polymers have the merits of high conductivity, and hence was attempted as electrode materials in batteries as soon as their discoveries. However, conducting polymers showed poor electrochemical performance and were baring vague charge storage mechanisms. Here, we reported a strategy to reveal the charge storage mechanisms of conducting polymers by constructing isomers and using polypyridines as a proof-of-concept. Polypyridines were rarely studied and its redox activity was still not clear. Our results indicated that every pyridine ring could accept one electron and the dimer unit with adjacent C=N groups could gain one more electron through chelation effects with Li ions. The electron transferred number and the chelation effects could be quantified by the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectroscopy and verified by density functional theory (DFT) calculations. As a result, one of the polypyridine isomers delivered the highest capacity of 504 mAh g^-1 after deducting the contribution of conductive additives. This work provides a universal way to reveal the charge storage mechanism and highlights the significance of adjacent active centers to form chelation with Li ions and hence enhance the performance of organic batteries.