Electrochemical activation strategy assisted morphology engineering Co-Fe layered double hydroxides for oxygen hydrogen evolution and supercapacitor.

CoFe-LDH after cyclic voltammetry is a kind of high efficiency supercapacitor and electrocatalytic multifunctional electrode material. [Display omitted] • The morphology of the CoFe-LDH-X can be regulated by electrochemical activation strategy. • Abundant grain boundaries not only provide more chemical active sites, but also reduce the energy barrier of OER. • The optimal CoFe-LDH exhibits superior performance for supercapacitor and OER. Regulating the intrinsic properties of the transition-metal layered double hydroxide (LDH) material is a promising strategy to improve the performance of oxygen evolution reaction (OER) and supercapacitor. Herein, a facile, low-cost and convenient electrochemical cyclic voltammetry (CV) activation strategy is reported. We demonstrate that electrochemical activation could regulate the morphology, crystal structure and electronic states of the Co-Fe layered double hydroxides (CoFe-LDH), thus significantly increasing the active site and electron transfer rate. As a result, in 1 M KOH, after 200 cycles CV activation CoFe-LDH (CoFe-LDH-200) has extremely low overpotential (360 mV at 100 mA cm−2) and Tafel slope (38.6 mV dec-1). Meanwhile, the CoFe-LDH-200 has the specific capacitance of 4662.2 mF cm−2 and good cycle stability (133.8 % after 10,000 cycles). Therefore, this method opens a novel insight for developing LDH in the field of supercapacitor and electrochemical water splitting. [ABSTRACT FROM AUTHOR]