Biligand metal-organic coordination polymer to prepare high N-doped content and structure controllable porous carbon with high-electrochemical performance

Abstract

N-doped content, N species and microstructure are crucial factors to control the energy storage ability of carbon-based materials. Herein, molecular engineering of metal-organic coordination polymers (MOCPs) by introducing two types of ligands to construct biligand MOCPs is proposed for the first time. Nitrogenous heterocyclic ligand 4,4′-bipyridine (BPD) and one of the aromatic amine ligands (p-phenylenediamine (PPD), 4,4′-diaminobiphenyl (AMP) and 3,3′-diaminobenzidine (DAB)) are selected to perform double-coordination reaction with different metal ions. Biligand MOCPs ([Co3(BPD)2(PPD)10Cl6]n, [Ni(BPD)(AMP)3Cl2]n and [Co3(BPD)2(DAB)5Cl6]n) have been successfully synthesized and employed as precursors to prepare N-doped porous carbons, referring as BPCCo, BACNi and BDCCo, respectively. Precise control over N-doped content, N species and microstructure has been fulfilled in these biligand MOCP derived N-doped porous carbons. As-prepared BPCCo, BACNi and BDCCo possess high nitrogen content of 11.39, 8.26 and 9.94 at.% and excellent gravimetric specific capacitance of 402, 316 and 303 F g−1, respectively. The BPCCo, BACNi and BDCCo assembled symmetric supercapacitors show outstanding energy density of 16.50, 13.38 and 12.98 W h kg−1, respectively. The pioneering strategy to molecularly engineer MOCP paves a new avenue in structure controlling over porous carbons. This concept can be further broadened to design component of co-polymers, polymer blends and organic synthetic materials as precursors to obtain expected carbon structures and desired properties.