A D–A type polymer as an organic cathode material for sodium-based dual-ion batteries with 3.0 V output voltage

Abstract

Organic cathode materials for rechargeable metal-ion batteries have attracted much attention, while their applications are still limited by the unsatisfactory voltage platform owing to the low conductivity and high solubility...

A donor–acceptor (D–A) conjugated polymer for fast storage of anions

“…The dual‐ion full cells still delivered a capacity of 102.6 mAh g −1 at 2 A g −1 after 1000 cycles (Figure 4d and Figure S39). The discharge voltage, rate performance, and cycling performance of the p‐TTPZ//graphite full cells exceeded most of the reported organic material‐based full cells [39] …”

“…The discharge voltage, rate performance, and cycling performance of the p-TTPZ// graphite full cells exceeded most of the reported organic material-based full cells. [39]…”

“…The D-A molecular structure is beneficial to charge transfer and transport, and therefore could endow the material with excellent reaction kinetics and rate performance for batteries, [38] which, however, was rarely reported. [39] Herein, we reported a copolymer (p-TTPZ) consisting of dihydrophenazine (PZ) [40][41][42] and thianthrene (TT) [26,43] units (Figure 1a). Although both of them are p-type monomers, the combination of PZ and TT resulted in the charge transfer.…”

Azobenzene-Phenazine-Based D–A Polymer as a Highly Efficient Bipolar Cathode for Sodium-Ion Batteries

“…More importantly, the easily tunable structures of organic compounds provide a wider option for electrode material (OEM) design. − Unlike inorganic materials, OEMs usually show less structural changes during charge/discharge and can allow the doping/dedoping of ions with various radii (e.g., metal ions and anions) . OEMs can be classified based on their embedded ions or redox mechanism: p-type cathodes for anion doping and n-type materials for cation storage. , n-type cathodes such as carbonyl compounds usually show high specific capacities, yet the low redox potential inhibits their applications. − In contrast, by dedoping/doping anions, p-type OEMs usually present higher redox potential (>2.8 V vs Na + /Na) and are expected to achieve higher energy density . In SIBs using p-type cathodes, both cations and anions work as charge carriers; hence the corresponding cell is called a dual-ion battery. , Generally, p-type organic cathodes include phenothiazine, thianthrene, polythiophene, dihydrophenazine derivatives, and nitriloyl derivatives. − Despite their high working voltages, drawbacks still existed: (1) low theoretical specific capacity; (2) the side reactions occurring at high voltage may lead to irreversible capacity as well as low Coulombic efficiency; (3) the organic electrodes tend to show low electronic conductivity and severe dissolution in the electrolyte, ending up with poor electrochemical performances. , Yet the electronic properties of organic electrodes are mainly determined by molecular structures.…”

“…17−19 In contrast, by dedoping/doping anions, ptype OEMs usually present higher redox potential (>2.8 V vs Na + /Na) and are expected to achieve higher energy density. 20 In SIBs using p-type cathodes, both cations and anions work as charge carriers; hence the corresponding cell is called a dualion battery. 21,22 Generally, p-type organic cathodes include phenothiazine, thianthrene, polythiophene, dihydrophenazine derivatives, and nitriloyl derivatives.…”