Pre‐Polymerization Enables Controllable Synthesis of Nanosheet‐Based Porphyrin Polymers towards High‐Performance Li‐Ion Batteries

Abstract

The precise regulation of nucleation growth and assembly of polymers is still an intriguing goal but an enormous challenge. In this study, we proposed a pre‐polymerization strategy to regulate the assembly and growth of polymers by facilely controlling the concentration of polymerization initiator, and thus obtained two kinds of different nanosheet‐based porphyrin polymer materials using tetrakis‐5,10,15,20‐(4‐aminophenyl) porphyrin (TAPP) as the precursor. Notably, due to the π–π stacking and doping of TAPP during the preparation process, the obtained PTAPP‐nanocube material exhibits a high intrinsic bulk conductivity reaching 1.49×10−4 S m−1. Profiting from the large π‐conjugated structure of porphyrin units, closely stacked layer structure and excellent conductivity, the resultant porphyrin polymers, as electrode materials for lithium ion batteries, deliver high specific capacity (≈650 mAh g−1 at the current density of 100 mA g−1), excellent rate performance and long‐cycle stability, which are among the best reports of porphyrin polymer‐based electrode materials for lithium‐ion batteries, to the best of our knowledge. Therefore, such a pre‐polymerization approach would provide a new insight for the controllable synthesis of polymers towards custom‐made architecture and function.

High Active Material Loading in Organic Electrodes Enabled by an in‐situ Electropolymerized π‐Conjugated Tetrakis (4‐Aminophenyl) Porphyrin

“…The contribution of conductive carbon to the capacity is in general negligible (Figure S7) and no porphyrin cathodes containing 70 wt % of active material have been reported with such high capacities so far, to the best of our knowledge. Until now, research on TAPP for batteries, was done by Han et al ., [20] who reported on a pre‐polymerized aminophenyl‐porphyrin complex which was utilized as an anode material and displayed high specific discharge capacities of up to 650 mAh/g at 100 mA/g. The polymers were assembled into nanosheets in an aqueous solution which improved the bulk conductivity at room temperature.…”

“…From the literature, [36] it is known that tetraaminophenyl‐porphyrins are able to undergo a polymerization reaction by forming a dihydrophenazine bond to build larger networks (Figure 4a). So far, the polymerization of aminophenyl‐porphyrins was either performed by ex ‐situ pre‐polymerization using Fe 3+ ‐ions as reacting agent [20] or in‐situ , where the porphyrin monomers were dissolved in the electrolyte and then immobilized during the cycling process on an electrode surface [36c] . Despite the simplicity of the second pathway, it just leads to thin films of polymers and is rather impractical for large scale energy applications like batteries.…”

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

“…Hence, organic cathode materials have recently attracted abundant attention and various organic cathode materials were gradually reported in the electrochemical energy-storage (EES) systems. For example, quinones, − phthalocyanines, − porphyrins, − conductive polymers, − organosulfur compounds, − etc. were continuously utilized in the rechargeable organic lithium-based batteries (ROLBs).…”

Controlled Synthesis of Mesoporous π‐Conjugated Polymer Nanoarchitectures as Anodes for Lithium‐Ion Batteries

“…As shown in Figure 5b, all polymerized samples displayed one broad diffraction peak near 20°, which can be attributed to the periodicity parallel of π ‐conjugated polymer skeleton. [ 22 ] The disappearance of GO peak suggested that the mPTAPB‐modified process could greatly promote structural heterogeneity.…”