Zhou Yangmei, Huang Xiuhui, Chen Xi, He Fangfang, Chen Di, Sun Xiujuan, Tan Songting, Gao Ping
Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, P. R. China.
Smart Devices and High-End Equipment Lab, Foshan (Southern China) Institute for New Materials, Suiyan West 92, Foshan 528247, P. R. China.
ACS Appl Mater Interfaces. 2022 Sep 14;14(36):40862-40870. doi: 10.1021/acsami.2c09649. Epub 2022 Aug 31.
Organic cathode materials have recently attracted abundant attention due to their flexible structural tunability and recyclability. However, the low intrinsic electrical conductivity and high solubility in electrolytes of organic electrode materials have significantly limited their practical application. Herein, we present [5,15-bis(ethynyl)-10,20-difurylporphinato] copper(II) (CuDEOP) as a new cathode for rechargeable organic lithium batteries (ROLBs). The combination of both ethynyl and furyl groups of the CuDEOP cathode with a nanorod structure renders it with enhanced structural stability and an extended delocalized π-electron system to deliver excellent cycling stability (capacity retention of 76% after 6000 cycles) and a high power density (16 kW kg). The furyl electroactive groups participate in charge storage contribution to achieve a reversible six-electron-transfer redox reaction in a specific voltage range. The mechanism characterizations indicate that the nitrogen atoms on the porphyrin ring act as active sites to alternatively store both PF anions and Li cations, and the charge storage process is a pseudocapacitive-dominated reaction. This observation will offer a new avenue for designing functionalized molecules for electrochemical energy-storage (EES) systems.
有机阴极材料因其灵活的结构可调节性和可回收性，近来受到了广泛关注。然而，有机电极材料固有的低电导率以及在电解质中的高溶解性，严重限制了它们的实际应用。在此，我们展示了[5,15-双（乙炔基）-10,20-二呋喃基卟啉]铜（II）（CuDEOP）作为可充电有机锂电池（ROLBs）的新型阴极。CuDEOP阴极的乙炔基和呋喃基与纳米棒结构相结合，使其具有增强的结构稳定性和扩展的离域π电子体系，从而实现出色的循环稳定性（6000次循环后容量保持率为76%）和高功率密度（16 kW kg）。呋喃基电活性基团参与电荷存储作用，在特定电压范围内实现可逆的六电子转移氧化还原反应。机理表征表明，卟啉环上的氮原子作为活性位点，交替存储PF阴离子和Li阳离子，且电荷存储过程是以赝电容为主导的反应。这一发现将为设计用于电化学储能（EES）系统的功能化分子提供一条新途径。
