Microparticles with hetero-nanointerfaces: controlled assembly of cobalt hydroxide and nickel hydroxide nanoclusters towards improved electrochemical functions†
The ultimate control of the interfaces of nanocomposite materials is essential to tailor and improve their physical/chemical properties in applications such as catalysis and energy storage and production. Fabrication and co-assembly of a variety of nanostructured colloids are promising ways to design the interface of materials in the nano-scale toward high functionality. In this study, we demonstrate the synthesis of colloids of nanocluster-sized (∼2 nm) cobalt and nickel hydroxides and their assembly into microparticles that present hetero-nanointerfaces. The electrochemical properties were investigated to elucidate the effect of the hetero-nanointerface. Microparticles with hetero nanostructures composed of cobalt and nickel hydroxide nanoclusters revealed improved mass specific capacity (91.4 mA h g−1) compared with the respective microparticles with homo-nanointerfaces (cobalt hydroxide, 15.8 mA h g−1; nickel hydroxide, 64.4 mA h g−1). Further investigation suggests that the introduced hetero-nanointerface leads to lower charge transfer resistance and improved electrochemical properties. The synthetic concept demonstrated here is expected to create unique hetero-nanointerfaces for various materials with a wide-range of chemical compositions towards improved and novel functionalities.