3D Hierarchical Co-Al Layered Double Hydroxides with LongTerm Stabilities and High Rate Performances in Supercapacitors

Three-dimensional (3D) flower-like Co-Al layered double hydroxide (Co-Al-LDH) architectures composed of atomically thin nanosheets were successfully synthesized via a hydrothermal method in a mixed solvent of water and butyl alcohol. Owing to the unique hierarchical structure and modification by butyl alcohol, the electrochemical stability and the charge/mass transport of the Co-Al-LDHs was improved. When used in supercapacitors, the obtained Co-Al-LDHs deliver a high specific capacitance of 838 F g(-1) at a current density of 1 A g(-1) and excellent rate performance (753 F g(-1) at 30 A g(-1) and 677 F g(-1) at 100 A g(-1)), as well as excellent cycling stability with 95% retention of the initial capacitance even after 20,000 cycles at a current density of 5 A g(-1). This work provides a promising alternative strategy to enhance the electrochemical properties of supercapacitors.