Ternary NiCoP nanoparticles assembled on graphene for high-performance lithium-ion batteries and supercapacitorsElectronic supplementary information (ESI) available: Materials including methods, TEM images of the NiCoP/G hybrid after the treatment, XRD and EDX of the samples, Raman spectrum of the NiCoP/G hybrid, discharge-charge voltage profiles of the NiCoP/G hybrid. See DOI: 10.1039/c7ra02910a

Transition metal phosphides have received considerable interest for electrochemical energy storage/conversion and catalysis. In this work, we designed a unique hybrid of NiCoP nanoparticles adhered on quasi-planar structured graphene by assembling 8.5 nm ternary NiCoP nanoparticles on graphene through a solution-phase self-assembly strategy. The NiCoP catalyst in the form of small-size particles wrapped in graphene provided more active sites, a buffer for volume alteration and enhanced conductivity for electrochemical reactions. Typically, the hybrid catalyst demonstrates a high specific capacity of around 532 mA h g −1 , excellent cycling stability and superior rate performance when the hybrid material is evaluated as an anode material for lithium-ion batteries, and it shows excellent electrochemical properties with a specific capacitance of 646 F g −1 at 4 A g −1 , maintaining 91% of this initial value after 2000 cycles functioning as a supercapacitor. We demonstrate that ternary NiCoP nanoparticles can be self-assembled on graphene at room temperature by a solution-phase method and our electrode materials exhibit a high performance for LIBs and supercapacitors.