3D Hierarchical Co–Al Layered Double Hydroxides with Long-Term 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. [Image: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s40820-016-0121-5) contains supplementary material, which is available to authorized users.