ABSTRACT
The small molecule 5,15-di(thiophen-2-yl) porphyrin (TP) was developed for new dual-ion symmetric organic batteries (DSOBs). It delivered a capacity of 150 mA h g-1 at 0.2 A g-1 with a high voltage of 2.7 V, and up to 1500 cycles were achieved. This work offers a new approach for developing high-performance dual-ion organic symmetric batteries.
ABSTRACT
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.
ABSTRACT
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]â MII (M=2 H, Cu (CuTTP)) are proposed as new stable organic electrodes. Enhanced cycling stability is obtained by a temperature-induced inâ situ polymerization strategy of porphyrin molecules. The resulting polymer exhibits excellent cycling stability up to 10 00â cycles even at a high current density (1000â 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 72â mAh g-1 is achieved after 600â cycles at 1000â mA g-1 . This strategy would offer a new approach to developing stable energy storage bipolar materials in organic-based devices at high temperature.
