Template-assisted synthesis of NiP@CoAl-LDH nanotube arrays with superior electrochemical performance for supercapacitors

A novel NiP@CoAl-LDH nanotube arrays (NiP@CoAl-LDH NTAs) are successfully designed on Ni foam via template-assisted electrodeposition process. The unique nanotube arrays can provide a short diffusion path for electrolyte ions and a high utilization rate for electrode materials. As a consequence, the obtained NiP@CoAl-LDH NTAs electrode presented the superior electrochemical performances, which demonstrated an areal specific capacity of 0.67 C cm−2 (556 C g−1) at 1 mA cm−2 and a high capacity retention of 74.1% at 20 mA cm−2, much higher than that of NiP NTAs and CoAl-LDH electrodes. The asymmetric supercapacitor device (ACS device) also displayed predominant electrochemical properties, such as high specific capacity of 156.1 C g−1 at 2 mA cm−2 and energy density of 37.18 Wh kg−1 at a power density of 0.45 kW kg−1. Besides, the specific capacity of ACS device maintained 95.50% of the initial specific capacity at 6 mA cm−2 after 4000 cycles, indicating its potential applications in long-term cycle life supercapacitor. These results illustrate the promise of NiP@CoAl-LDH NTAs as electrode for supercapacitor.