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Cite This: ACS Appl. Mater. Interfaces 2018, 10, 9104−9115
Interpenetrated and Polythreaded CoII-Organic Frameworks as a Supercapacitor Electrode Material with Ultrahigh Capacity and Excellent Energy Delivery Efficiency Kuaibing Wang,†,‡ Xiaoran Cao,† Saier Wang,† Wenjia Zhao,† Jiangyan Xu,† Zikai Wang, and Hua Wu*,† †
Jiangsu Key Laboratory of Pesticide Sciences, Department of Chemistry, College of Science, Nanjing Agricultural University, Nanjing 210095, P. R. China ‡ State Key Laboratory of Coordination Chemistry, Coordination Chemistry Institute, Nanjing University, Nanjing 210093, P. R. China S Supporting Information *
ABSTRACT: Synthesizing kinetically stable coordination polymers (CPs) through ligand functionalization can effectively improve their supercapacitive performances. Herein, we have successfully synthesized three novel and topological CoCPs by varying the flexible N-donor ligand and inorganic anions, namely, interpenetrated [Co(HTATB)(o-bib)]·H2O, extended two-dimensional (2D) layered Co(HTATB)(m-bib)· 2H2O, and three-dimensional (3D) Co(HTATB)(m-bib), where bib is the flexible N-donor bis((1H-imidazol-1yl)methyl)benzene linker (where o- and m- refer to ortho and meta positions, respectively) ligand and HTATB is the partial deprotonation mode from 4,4′,4″-s-triazine-2,4,6-triyltribenzoic acid. Various Co-CPs have been directly applied in the field of supercapacitors. All these framework materials exhibit high capacitance, excellent energy delivery efficiency, and good cycling performance. For instance, the maximum specific capacitance for penetrated 3D networks is 2572 F g−1 at 2.0 A g−1, and the mean energy delivery efficiency is up to 92.7% based on the tested current densities. Compared with extensional 2D layered and 3D networks, the 3D interpenetrated and polythreaded architectures could provide more active sites and thus promote fast charging and discharging processes. Furthermore, the Li+ uptake−release abilities of the Co-based CPs are also investigated, and the initial discharge capacity value for the 3D interpenetrated structures can reach up to 1792 mA h g−1 at a current density of 50 mA g−1. KEYWORDS: CoII-organic frameworks, supercapacitor, ultrahigh capacity, energy delivery efficiency, 3D networks, interpenetrated
1. INTRODUCTION Supercapacitors (SCs) are one of the energy-storage systems that have been considered as the next-generation portable devices because of the features such as long cycle life, absence of memory effect, operational safety, and high power density.1−15 Compared with batteries, SCs not only store equal energy but also recharge in a very short time. Most importantly, SCs can provide the high power needed during acceleration and braking when they integrate with other energystorage systems, such as fuel cells, batteries, and so on.16,17 However, the energy density reported for the current SCs is less than 10 W h kg−1, which is extremely low in contrast with lead−acid (
