Ethynyl and Furyl Functionalized Porphyrin Complexes as New Organic Cathodes Enabling High Power Density and Long-Term Cycling Stability

Regulating the Metal Nodes of In Situ Electropolymerized Metal-Organic Coordination Polymers for High Performance LIBs

Metal-organic coordination polymers (MOPs) comprised of redox-active organic moieties and metal ions emerge as an important class of electroactive materials for battery applications. The bipolar two transition metal-based (Fe and Co) coordination complexes bearing terpyridine-triphenylamine ligand are used as models to investigate the relationships between structure and electrochemical performance. It turned out that the choice of central metal atom has a profound influence on the practical voltage window and specific capacity. The high-performing poly(FeL)n electrode exhibits a reversible capacity of 272.5 mAh g-1 after 100 cycles at 50 mA g-1, excellent cycling stability up to 4000 cycles at 5A g-1 (capacity ration:83.1%), and excellent rate capacity. The poly(CoL)n electrode exhibits a significantly lower capacity of 107 mAh g-1 at the 100th cycle and inferior stability (54 mAh g-1 after 4000 cycles at 5A g-1, capacity retention: 38.7%). DFT analysis indicates that the metal center directly influences the electron cloud density of the metal-terpyridine structure, which in turn affects the redox activity of the polymer by varying the affinity to lithium ions and the charge transfer efficiency. These findings highlight the importance of metal centers in coordination polymers, providing direct guidance for the exploration of MOPs as novel resource-friendly cathode materials.

Ferrocene Appended Porphyrin-Based Bipolar Electrode Material for High-Performance Energy Storage

The versatile properties of bipolar organic electrode materials have attracted considerable attention in the field of electrochemical energy storage (EES). However, their practical application is hindered by their inherent limitations including low intrinsic electrical conductivity, low specific capacity, and high solubility. Herein, a bipolar organic molecule combining both porphyrin and ferrocene moieties (CuDEFcP) [5,15-bis(ethynyl)-10,20-di ferrocenyl porphinato]copper(II)) has been developed. It is proposed as a new organic electrode material with multifunctional application for rechargeable organic lithium-based batteries (ROLBs) and dual-ion organic symmetric batteries (SDIBs). Superior performance was delivered as cathode material in lithium based dual-ion batteries (LDIBs), with a high initial discharge capacity of 300 mAh. g-1 at 0.2 A. g-1 and a reversible capacity of 58 mAh. g-1 after 5000 cycles at 1 A. g-1. However, employing it as an anode material in lithium-ion batteries (LIBs), a reversible capacity of 295 mAh. g-1 at 0.2 A. g-1 was delivered. In SDIBs, in which CuDEFcP is used as both anode and cathode, an average discharge voltage of 2.4 V and an energy density of 261 Wh.kg-1 were achieved.

Advances and prospects of porphyrin derivatives in the energy field

At present, porphyrin is developing rapidly in the fields of medicine, energy, catalysts, etc. More and more reports on its application are being published. This paper mainly takes the ingenious utilization of porphyrin derivatives in perovskite solar cells, dye-sensitized solar cells, and lithium batteries as the background to review the design idea of functional materials based on the porphyrin structural unit in the energy sector. In addition, the modification and improvement strategies of porphyrin are presented by visually showing the molecular structures or the design synthesis routes of its functional materials. Finally, we provide some insights into the development of novel energy storage materials based on porphyrin frameworks.

A bipolar pyridine-functionalized porphyrin with hybrid charge-storage for dual-ion batteries

A metal-free porphyrin T4PP with a pyridine group is proposed as a new electrode for lithium/sodium-based dual-ion batteries (LDIBs/SDIBs). The electrochemical performance and reaction mechanism of T4PP are explored thoroughly. The extended porphyrin conjugated structure by the pyridine groups enables an excellent cycle life (5000 cycles) and a high-power density (18.7 kW kg^-1). A hybrid charge-storage mechanism with the contribution of both cations and anions benefits fast charge transfer.