Narrow band gap conjugated polymer photocatalysts containing dithieno[3,2-b:2′,3′-d]thiophene-S,S-dioxide show an attractive photocatalytic hydrogen evolution rate of 16.32 mmol h−1 g−1 under visible light irradiation.

Recent studies have demonstrated that dihydrophenazine (Pz) with high redox-reversibility and high theoretical capacity is an attractive building block to construct p-type polymer cathodes for dual-ion batteries. However, most reported Pz-based polymer cathodes to date still suffer from low redox activity, slow kinetics, and short cycling life. Herein, a donor-acceptor (D-A) Pz-based conjugated microporous polymer (TzPz) cathode is constructed by integrating the electron-donating Pz unit and the electron-withdrawing 2,4,6-triphenyl-1,3,5-triazine (Tz) unit into a polymer chain. The D-A type structure enhances the polymer conjugation degree and decreases the band gap of TzPz, facilitating electron transportation along the polymer skeletons. Therefore the TzPz cathode for dual-ion battery shows a high reversible capacity of 192 mAh g −1 at 0.2 A g −1 with excellent rate performance (108 mAh g −1 at 30 A g −1 ), which is much higher than that of its counterpart polymer BzPz produced from 1,3,5-triphenylbenzene (Bz) and Pz (148 and 44 mAh g −1 at 0.2 and 10 A g −1 , respectively). More importantly, the TzPz cathode also shows a long and stable cyclability of more than 10 000 cycles. These results demonstrate that the D-A structural design is an efficient strategy for developing high-performance polymer cathodes for dual-ion batteries.

It is challenging for polymer photocatalysts to achieve high photocatalytic performance under visible light due to their weak light absorption in visible light region. Herein, a universal strategy for boosting the photocatalytic activity of donor-acceptor (D-A) conjugated polymer photocatalysts upon visible light irradiation by inserting a π-spacer of thiophene unit between the electron donors and acceptors to form a D-π-A molecular structure is reported. The introduction of thiophene unit with narrow band gap can enhance the conjugation degree of the polymer chains and extend the light absorption range. Meanwhile, the introduction of thiophene spacer through ternary copolymerization also enables the controllability on the chemical structure of the resulting D-π-A polymers by altering the feed ratio between the electron donors and acceptors. The optimized D-π-A copolymer photocatalyst shows an impressive hydrogen evolution rate (HER) of 78.4 mmol h -1 g -1 under visible light irradiation, and the HER could be further improved to 127.9 mmol h -1 g -1 under UV-vis light irradiation by loading 1 wt% Pt co-catalyst. More importantly, this strategy can also be extended to other polymeric photocatalysts with different donor and acceptor units, demonstrating the universality for enhancing the photocatalytic activity of polymeric photocatalysts.

It is fundamentally challenging for cathode materials to achieve long life, high capacity, and fast kinetics in rechargeable aluminum batteries, due to the strong electrostatic interaction between Al3+ and the host materials. Herein, the redox‐active dihydrophenazine (Pz) is coupled with pyrene (Py) or biphenyl (Ph) to develop two conjugated microporous polymers of PyPz and PhPz as AlCl4−‐hosting cathodes for aluminum dual‐ion batteries (ADIBs). It is revealed that the planar Py unit endows PyPz with an extended conjugated skeleton and a higher surface area than PhPz produced from the Ph unit with a twisted structure, thus leading to a higher redox activity for PyPz. Hence, the PyPz cathode delivers a much higher capacity of 231 mAh g−1 than PhPz (137 mAh g−1). Its porous structure and insolubility also ensure PyPz shows a superior rate performance and exceptional cyclability over 100 000 cycles. Meanwhile, the feature of fast kinetics for AlCl4− storage also allows PyPz to operate well at not only a low temperature (−30 °C) but also a high areal capacity of 2.53 mAh cm−2. These findings suggest that redox‐active conjugated polymers are promising advanced organic cathodes for sustainable ADIBs, where the electrochemical performance can be significantly enhanced by rational structural design.

Redox-active carbonyl-containing compounds have received extensive attention as cathode materials for sodium-ion batteries (SIBs) because of their excellent attributes, including elemental sustainability, high theoretical capacity, diverse structures, and tunable properties. However, the storage of Na+ in most carbonyl-based cathode materials is plagued by the low capacity, unsatisfying rate performance, and short cycling life. Herein, we develop a series of anthraquinone-based conjugated polymer cathodes consisting of anthraquinone and benzene with different linking patterns. It reveals that the linkage sites on benzene ring could affect the electronic structures of the resulting polymers and thus their charge-storage capabilities. The 1,2,4,5-linkage on benzene leads to a high surface area, a narrow band gap, and the lowest unoccupied molecular orbital for the resulting polymer PBAQ-3. As a cathode for SIBs, it delivers a high capacity of around 200 mAh g–1 and excellent rate performance (105 mAh g–1 at 200 C) as well as stable cycling with a capacity retention of 95.8% after 1000 cycles at 0.05 A g–1 and 83.1% after 40000 cycles at 3 A g–1. Our findings highlight the influence of linking patterns of the building blocks on the electrochemical performance of organic electrodes.