LAUSR

Abstract Though redox-based electrode materials with a high surface-area are expected to bridge the gap between supercapacitors and rechargeable batteries in energy-storage applications, full utilization of the inherent electoactivity is frequently hindered by the limited diffusion of electrolytes, paricularly during high-rate charge/discharge. Here, we demonstrate the electrochemical properties of Ni(OH) 2 nanoplatelets that are vertically grown on graphene by employing poly(amidoamine) dendrimers as growth directing agents and as linkers. By virtue of the structural features, Ni(OH) 2 electrodes deliver a maximum specific capacity of 1226 Cg −1 (2043 Fg −1 ) at 5 mVs −1 . The electrodes also retain a substantial capacity at high charge/discharge rates (955 Cg −1 at 1 Ag −1 vs. 560 Cg −1 at 80 Ag −1 ). The cycability is also remarkable, exhibiting the capacity retention of 102% after 5000 cycles at 10 Ag −1 . These excellent electrochemical properties are contrasted with those of a composite prepared without dendrimers (496 Cg −1 at 5 mVs −1 ; 486 Cg −1 at 1 Ag −1 vs. 184 Cg −1 at 80 Ag −1 ; 78% retention). By virtue of Ni(OH) 2 nanoplatelets, an asymmetric full-cell coupled with a graphene electrode can deliver one of the highest energy densities ever reported (52–58 Whkg −1 ) with high power densities that range between 1.0 and 20.0 kWkg −1 .