A metal-free porphyrin T4PP with 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. Extended...

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Organic sodium-ion batteries (OSIBs) using eco-friendly organic materials as electrodes have recently received much attention. However, the practical applications of OSIBs are generally limited by the inherent disadvantages of organic electrodes, such as their low conductivity, poor stability, and high solubility in electrolytes. Herein, we presented [5,10,15,20-tetrathienylporphinato] M (II) (MTTP, M = 2H, Ni) as new electrode materials in sodium-organic batteries. The incorporation of thiophene functionalized groups and nickel (Ⅱ) ion in the molecular design of porphyrins enabled stable and excellent electrochemical performance in sodium storage systems. Benefiting from multiple charge storage sites and bipolar characteristic, the NiTTP anode has a reversible capacity of 434 mAh g−1 at a current density of 25 mA g−1. An excellent long-term cycling stability and high average voltage were obtained when NiTTP was used as a cathode. In a symmetrical battery, where NiTTP was used as both cathode and anode materials, a high average voltage of 2.3 V and a practical energy density of 93 Wh kg−1 was achieved. These results suggest that the thiophene-based porphyrin derivatives would be a promising electrode material for long-term organic sodium ion batteries for green and stable energy storage.

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Bipolar redox organic compounds have been considered as potential next‐generation electrode materials due to their sustainability, low cost and tunable structure. However, their development is still limited by the poor cycling stability and low energy density ascribed to high dissolution during cycling and the low conductivity of organic molecules. Herein, porphyrin‐based bipolar organics of [5,10,15,20‐tetrathienylporphinato] MII (M=2 H, Cu (CuTTP)) are proposed as new stable organic electrodes. Enhanced cycling stability is obtained by a temperature‐induced in situ polymerization strategy of porphyrin molecules. The resulting polymer exhibits excellent cycling stability up to 10 00 cycles even at a high current density (1000 mA g−1) in organic lithium‐/sodium‐based charge storage devices at 50 °C. In a symmetrical cell using CuTTP as both cathode and anode material a discharge capacity of 72 mAh g−1 is achieved after 600 cycles at 1000 mA g−1. This strategy would offer a new approach to developing stable energy storage bipolar materials in organic‐based devices at high temperature.