3D Binder-free conjugated microporous polymer carbon Aerogels@MnO2 cathode for High-Performance aqueous zinc ion batteries

Abstract

Binder-free MnO2-based cathodes are critical to the development of aqueous Zn//MnO2 batteries. Here, conjugated microporous polymer aerogels (CMPAs) with columnar, rod and linear shapes are successfully prepared through Sonogashira-Hagihara cross-coupling reaction. Using them as precursors, we obtain the integrated high-conductivity carbon-based aerogels (C-CMPAs) by pyrolysis. Secondly, MnO2 nanosheet arrays are uniformly grown on the surface of C-CMPAs nanotubes(C-CMPAs@MnO2) form a thin-walled cell configuration through a simple low temperature hydrothermal method. In this system, C-CMPAs serve as both current supporter and collector, while the cross-linked MnO2 flakes act as the active layer. This unique anisotropic structure not only greatly enlarges the contact area of electrode/electrolyte interfaces and supplies abundant electrochemically active sites, but shortens the Zn2+ ion insertion/extraction paths. Meanwhile, the high mechanical strength of core/shell structure between C-CMPAs and MnO2 renders long-term cycling life. Finally, binder-free C-CMPAs@MnO2-based aqueous zinc-ion batteries provide an unprecedented capacity of 670.7 mAh g−1 at 0.1 A g−1, good rate performance and excellent cycle stability (94.1% after 600 cycles). More importantly, the Zn//C-CMPAs@MnO2 aqueous battery provides high energy density of 536.6 Wh kg−1 at 80.3 W kg−1, superior to most similar reports, indicating the great potential of high-performance rechargeable batteries.