Electropolymerization stabilized bipolar metal coordination complex for high-performance dual-ion batteries.

• A bipolar cobalt coordination polymer bearing triphenylamine-pyridine ligand (poly(CoL) n) is reported. • In-cell electropolymerization effectively decreases solubility of poly(CoL) n in organic solution. • Dual-ion storage capability of poly(CoL) n originates from multiple redox sites of monomer. • The poly(CoL) n cathode delivered a high discharge specific capacity of 192.13 mAh/g at 0.05 A/g. • The poly(CoL) n cathode delivered a stable long-term cycling ability over 2000 cycles with 89% capacity retention at 5 A/g. Metal coordination complexes with remarkable redox activity and high working voltage are plagued by their limited specific capacity and sever dissolution problem. A bipolar cobalt-based coordination polymer (CoL) bearing both p-type and n-type active centers was synthesized via the in-situ electropolymerization method with collective merits of multiple redox sites, dual-ion storage capability, and excellent chemical stability. As-prepared electrodes delivered remarkable performances including a high discharge specific capacity of 192.13 mAh/g (at 0.05 A/g), stable cycling over 2000 cycles with 89% capacity retention (at 5A/g), and excellent rate capability. Moreover, the dual-ion storage processes were unveiled by ex-situ Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis. It provides insight to design and synthesis of electropolymerized bipolar electrode for high performance dual-ion batteries. [ABSTRACT FROM AUTHOR]