Boosted electrochemical properties from the surface engineering of ultrathin interlaced Ni(OH)(2) nanosheets with Co(OH)(2) quantum dot modification

Nanoscale surface engineering of electroactive architectures is of paramount importance in high-performance supercapacitor applications based on surface-controlled charge storage mechanisms. Herein, we exploit Co(OH)(2) quantum dots (CoQDs) as a surface modifier and report a simple and effective strategy for anchoring CoQDs on ultrathin interlaced Ni(OH)(2) nanosheets. Impressively, the 2D/0D heterostructure of CoQD-interspersed Ni(OH)(2) nanosheets (Ni(OH)(2)-CoQD) exhibits greatly enhanced capacitive behavior compared with pristine Ni(OH)(2) nanosheets, exhibiting a higher capacitance (3244 F g(-1)vs. 2124 F g(-1) at 5 mA cm(-2)), superior rate capability and better cycling stability. Density functional theory (DFT) calculations reveal the accumulation of additional electrons and reduced adsorption energy of OH- at the Ni(OH)(2)-CoQD interphase, which are the primary reasons for the enhanced electrochemical performance. An asymmetric full cell with Ni(OH)(2)-CoQD as the positive electrode has been fabricated, achieving a maximum energy density of 46 W h kg(-1) at 141 W kg(-1), and excellent cycling stability, where 84.1% of the initial capacitance is retained over 5000 cycles. This work brings a new opportunity to pseudoactive electrode material design by employing semiconductive quantum dots for surface modification.