Facile synthesis and incomplete sulfidation of nickel-cobalt-aluminum ternary layered hydroxide binder-free electrode with enhanced supercapacitor properties

Layered transition metal hydroxide, a clay-like material, possessing characteristics of large specific surface area, adjustable fraction, and plentiful active components make it a potential energy storage material, especially in the background of energy and environment crisis. Herein, comprehensive applications of cobalt-aluminum-based LDHs for supercapacitors are proposed. Binder-free electrodes were successfully synthesized such as Co 3 Al 1 -LDH/Ni, Ni 2 Co 1 Al 1 -LDH/Ni and Ni 1 Co 2 Al 1 -LDH/Ni using a rapid green hydrothermal approach. Subsequently, further sulfuration was carried out to obtain a heterostructure of sulfide/layered hydroxide. The electrochemical energy storage properties of binder-free electrodes were investigated, which show that the performance of ternary LDH electrode is better than that of binary one, and the incompletely sulfuration Ni 1 Co 2 S/Ni has the optimal electrochemical performance among all electrodes, with a specific capacitance of 2186 F g −1 at 1 A g −1 . The Ni 1 Co 2 S//AG hybrid supercapacitor (HSC) device assembled with Ni 1 Co 2 S as positive electrode and active graphene as negative electrode delivers an energy density of 13 Wh kg −1 at a power density of 749 W kg −1 , good rate capability and cycling stability. • Binary and ternary NiCoAl-LDHs were successfully synthesized in situ on nickel foam with vertical structures. • Incomplete sulfuration of NiCoAl-LDH was successfully achieved to form a heterostructure. • Construction of hybrid supercapacitors Ni 1 Co 2 S//AG HSC has better rate performance.