Porous Metal–Organic Frameworks Containing Reversible Disulfide Linkages as Cathode Materials for Lithium‐Ion Batteries

• Published in: ChemSusChem 2020-05, Vol.13 (9), p.2256-2263
• Main Authors: Shimizu, Takeshi, Wang, Heng, Matsumura, Daiju, Mitsuhara, Kei, Ohta, Toshiaki, Yoshikawa, Hirofumi
• Format: Article
• Language: English
• Subjects: Cathodes; Coordination polymers; Cycles; disulfide; Electrode materials; Electrolytes; Li metal batteries; Li-S batteries; Ligands; Lithium; Lithium batteries; Lithium-ion batteries; Metal-organic frameworks; Redox reactions
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201903471

Three porous disulfide‐ligand‐containing metal–organic frameworks (DS‐MOFs) and two nonporous coordination polymers with disulfide ligands (DS‐CPs) with various structural dimensionalities were used as cathode active materials in lithium batteries. Charge/discharge performance examinations revealed that only porous DS‐MOF‐based batteries exhibited significant capacities close to the theoretical values, which was ascribed to the insertion of electrolyte ions into the DS‐MOFs. The insolubility of porous 3 D DS‐MOFs in the electrolyte resulted in cycling performances superior to that of their 1 D and 2 D porous counterparts. Battery reactions were probed by instrumental analyses. The dual redox reactions of metal ions and disulfide ligands in the MOFs resulted in higher capacities, and the presence of reversible electrochemically dynamic S−S bonds stabilized the cycling performance. Thus, the strategy of S−S moiety trapping in MOFs and the obtained correlation between the structural features and battery performance could contribute to the design of high‐performance MOF‐based batteries and the practical realization of Li‐S batteries. Dynamic duo: Porous metal–organic frameworks containing disulfide ligands (DS‐MOFs) exhibit significant battery capacities owing to the reversible dual redox reactions of metal ions and disulfide ligands. Of the architectures tested, the porous 3 D DS‐MOFs have the best cycling performance, which is ascribed to their insolubility in the electrolyte during electrochemical reactions.