Xiangyue Kong

Organic materials are considered to have broad application prospects in energy storage systems due to their strong designability and abundant resources. Here, we report a triquinoxalinylene derivative tribenzoquinoxaline-5,10-dione (3BQ) containing high redox potential functional groups (CO and CN) and a large number of low redox potential functional groups (unsaturated carbon). This paper uses 3BQ as the cathode and anode to assemble all-organic symmetric batteries. Since 3BQ has denser active sites and a larger conjuated system than triquinoxalinylene (3Q), the 3BQ cathode has an initial capacity of 506 mA h g⁻¹ (C_theo = 515 mA h g⁻¹) at 0.2C, and the capacity of 3BQ and 3Q cathodes is 210 and 107 mA h g⁻¹ after 300 cycles at 1C. The large conjugated system and planar structure of 3BQ inhibit its dissolution in electrolytes and accelerate the charge transfer rate, resulting in good cycle stability and rate performance for batteries. The all-organic symmetric batteries assembled with pre-lithiated 3BQ and pristine 3BQ deliver an initial capacity of 483 mA h g⁻¹ at 0.2C, a capacity of 172 mA h g⁻¹ after 300 cycles and an energy density of 301 W h kg⁻¹. This work provides a strategy for the development of high-performance LIBs using organic materials as the cathode and anode.

From basic research to industry process, battery energy storage systems have played a great role in the informatization, mobility, and intellectualization of modern human society. Some potential systems such as Li, Na, K, Mg, Zn, and Al secondary batteries have attracted much attention to maintain social progress and sustainable development. As one of the components in batteries, electrolytes play an important role in the upgrade and breakthrough of battery technology. Since room‐temperature ionic liquids (ILs) feature high conductivity, nonflammability, nonvolatility, high thermal stability, and wide electrochemical window, they have been widely applied in various battery systems and show great potential in improving battery stability, kinetics performance, energy density, service life, and safety. Thus, it is a right time to summarize these progresses. In this review, the composition and classification of various ILs and their recent applications as electrolytes in diverse metal‐ion batteries (Li, Na, K, Mg, Zn, Al) are outlined to enhance the battery performances.