Pillared nickel-based metal-organic frameworks as electrode material with high electrochemical performance

A pillared nickel-based MOFs, Ni-2(bdc)(2)P (bdc is the 1,4-benzenedicarboxylic acid and P is dabco(1,4-diazabicyclo[2.2.2]-octane)), and Zn-doped pillared (Zn/Ni)(2)(bdc)(2)P are synthesized and their electrochemical properties as an electrode material are firstly evaluated. The Ni-2(bdc)(2)P electrode material has a specific capacity of 177.6C g(-1) and 48C g(-1) at 0.5 A g(-1) and 10 A g(-1), respectively. Much higher specific capacities of 298.5C g(-1) at 0.5 A g(-1) and 104 C g(-1) at 10 A g(-1) are obtained for the (Zn/Ni)(2)(bdc)(2)P, indicating good rate capability. In addition, the pillared (Zn/Ni)(2)(bdc)(2)P also possesses more stable cycling performance than the pillared Ni-2(bdc)(2)P. The excellent electrochemical performance of both Ni-2(bdc)(2)P and (Zn/Ni)(2)(bdc)(2)P can be attributed to their 3D framework structure with open channels and large surface area, hierarchical porous structure and high electrical conductivity. An asymmetric supercapacitor (ASC) (Zn/Ni)(2)(bdc)(2)P//AC is assembled to evaluate the practical application of (Zn/Ni)(2)(bdc)(2)P electrode. The assembled ASC possesses a high energy density of 12.2 W h kg(-1) at a power density of 371.5 W kg(-1) and excellent cycling performance. Furthermore, two assembled ASCs in series are used to light up a red and a yellow light-emitting diode (LED).