Volume 64, Issue 28 e202503151
Research Article

Dihydrophenazine Derived Pd6L12 Cage: Self-Assembly, Polyradical Cations, and Lithium Battery Cathode Application

Meng-Xiang Wu

Meng-Xiang Wu

State Key Laboratory of Petroleum Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062 China

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Yingli Li

Yingli Li

College of Materials, Chemistry and Chemical Engineering, Hangzhou Normal University, 2318 Yuhangtang Road, Hangzhou, Zhejiang, 311121 China

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Jiefan Liu

Jiefan Liu

Shanghai Key Laboratory of Magnetic Resonance, State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai, 200241 China

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Bin Huang

Bin Huang

State Key Laboratory of Petroleum Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062 China

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Qiong-Yan Hong

Qiong-Yan Hong

State Key Laboratory of Petroleum Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062 China

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Wei-Ling Jiang

Wei-Ling Jiang

State Key Laboratory of Petroleum Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062 China

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Yu Zhao

Yu Zhao

College of Materials, Chemistry and Chemical Engineering, Hangzhou Normal University, 2318 Yuhangtang Road, Hangzhou, Zhejiang, 311121 China

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Gaole Dai

Corresponding Author

Gaole Dai

College of Materials, Chemistry and Chemical Engineering, Hangzhou Normal University, 2318 Yuhangtang Road, Hangzhou, Zhejiang, 311121 China

E-mail: [email protected]; [email protected]; [email protected]; [email protected]

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Bingwen Hu

Corresponding Author

Bingwen Hu

Shanghai Key Laboratory of Magnetic Resonance, State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai, 200241 China

E-mail: [email protected]; [email protected]; [email protected]; [email protected]

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Xueliang Shi

Corresponding Author

Xueliang Shi

State Key Laboratory of Petroleum Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062 China

E-mail: [email protected]; [email protected]; [email protected]; [email protected]

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Hai-Bo Yang

Corresponding Author

Hai-Bo Yang

State Key Laboratory of Petroleum Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062 China

E-mail: [email protected]; [email protected]; [email protected]; [email protected]

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First published: 05 May 2025

Graphical Abstract

In this study, we synthesized a dihydrophenazine-based Pd6L12 coordination cage (Cage 1) with excellent redox activity. It can reversibly transform into its radical cation form (112•+) via electrochemical or chemical oxidation/reduction. Both forms' structures were determined by X-ray diffraction. In situ spectroelectrochemical techniques verified their redox reversibility and electrochromic behavior. Cage 1 was also used as a lithium battery cathode, with its redox behavior studied by in situ 2D EPR.

Abstract

In this study, we present the self-assembly of a dihydrophenazine-based Pd6L12-type coordination cage 1 showing excellent redox activity and demonstrate the use as the cathode for lithium batteries. The structure of cage 1 was confirmed by single-crystal X-ray diffraction analysis. The excellent reversible redox performance of 1 and its electrochromic properties induced by radical species were systematically characterized using in situ UV–vis–NIR and EPR spectroelectrochemistry. Notably, a highly stable radical cationic species 112•+, containing 12 radical cations, was successfully obtained through the chemical oxidation of 1, and its single-crystal structure was resolved. The excellent redox properties of 1 enable its application as a cathode material for lithium batteries. The 1|Li cell exhibited good cycling stability, nearly 100% coulombic efficiency, and an initial discharge capacity of 84 mAh g⁻¹ within a voltage range of 2.5–4.0 V. Furthermore, in situ 2D EPR experiments on lithium batteries visually revealed the excellent cycling stability of the 1-based cathode material and its reversible two-step electron transfer process. This study provides important insights into the design, synthesis, and properties of functionalized redox-active coordination cages, offering a reference for their application in energy storage and functional materials research.

Conflict of Interests

The authors declare no conflict of interest.

Data Availability Statement

Data involved in this work are included in this article and the corresponding supplementary materials. Deposition numbers CCDC 2404229 (for L), 2404230 (for 1), 2404232 (for 112•+), 2433324 (for 1(PF6)) contain the supplementary crystallographic data for this paper. These data are provided free of charge by the joint Cambridge Crystallographic Data Centre Access Structures service.

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