Controllable preparation of nickel cobalt manganese ternary metal-organic frameworks for high-performance supercapacitor

Abstract

In this study, Ni, Co and Mn metal-organic frameworks (MOFs, Ni2Co1-XMnX-MOFs-S, X = 0, 0.25, 0.5) nanorods are successfully obtained by a one-step hydrothermal method under the aid of C12H25SO4Na (SDS). The morphology and the size of the nanorods can be controlled by changing the doping method and content of Mn, resulting in the different electrochemical performances. The study proves that SDS has a great influence on the capacitance of the ternary metal NiCoMn-MOFs. Research results show that the optimized Ni2Co0.75Mn0.25-MOFs-S displays a capacitance of 1428 F·g−1 at current density of 1 A·g−1. Meanwhile, controlling partial substitution of Mn is beneficial to improve the stability of MOFs, such as the charge-discharge cycle stability of Ni2Co0.75Mn0.25-MOFs-S is high to 83.5 % after 3000 cycles. The energy density of the asymmetric supercapacitor (Ni2Co0.75Mn0.25-MOFs-S//AC) is 38.10 Wh·kg−1 at a power density of 884.38 W·kg−1. In addition, the act of Mn on improving material stability is studied.