Hierarchical Architectures Of Layered Double Hydroxide Films Anode And Cathode Material With Pseudocapacitive Performance

The performances of pseudocapacitors usually depend heavily on their hierarchical architectures andcomposition. A three dimensional (3D) hierarchical NiAl layered double hydroxide/multiwalled carbon nanotube/nickel foam (NiAl-LDH/MWCNT/NF) electrode are prepared by a facile three-step fabrication method:in situ hydrothermal growth of NiAl-LDH film on a Ni foam, followed by direct chemical vapor deposition growth of dense MWCNTs onto the NiAl-LDH film and finally the growth of NiAl-LDH onto the surface of the MWCNTs via an in situ hydrothermal process in the presence of surfactant sodium dodecyl sulfate (SDS).The MWCNT surface was fully covered by NiAl-LDH hexagonal platelets. Eventually we obtained the hierarchical film.The NiAl-LDH/MWCNT/NF electrode has an areal loading mass of 5.8 mg LDH per cm2 of MWCNT/NF surface. It also possesses exceptional areal capacitance (7.5 F cm-2), specific capacitance (1293 F g-1), and cycling stability (83% of its initial value was preserved after 1000 charge-discharge cycles). Compared with NiAl-LDH/NF electrode(areal capacitance 5.6 F cm-2, specific capacitance 938 F g-1 and 69% cycling stability), the electrochemical performance of NiAl-LDH/MWCNT/NF electrode has a significant enhancement. The NiAl-LDH/MWCNT/NF mateial is thus a highly promising electrode with potential applications in electrochemical energy storage. At the same time, the FeⅡFeⅢ-LDH (GR) and FeⅡFeⅢ-LDH/CNT was prepared by a coprecipitation process using sulfate as Fe source, and sodium hydroxide as precipitant. They possesses specific capacitance 461 F g-1 and 980 F g-1 separately. The experiments demonstrated that the introduction of CNT lead to capacitance performance increase. The NiAl-LDH/MWCNT/NF and Fe" FeⅢ -LDH/CNT electrode have great potential applications in electrochemical energy storage.