Multifunctional 0D–2D Ni2P Nanocrystals–Black Phosphorus Heterostructure

0D transition metal phosphides (TMPs) nanocrystals (NCs)–2D ultrathin black phosphorus (BP) heterostructure (Ni₂P@BP) have been synthesized via a facile sonication‐assisted exfoliation followed by a solvothermal process. Compared with the bare BP, the specially designed Ni₂P@BP architecture can enhance the electrical conductivity (from 2.12 × 10² to 6.25 × 10⁴ S m^–1), tune the charge carrier concentration (from 1.25 × 10¹⁷ to 1.37 × 10²⁰ cm^–3), and reduce the thermal conductivity (from 44.5 to 7.69 W m^–1 K^–1) at 300 K, which can be considered for multiple applications. As a result, the Ni₂P@BP exhibits excellent Li storage properties and high hydrogen evolution reaction electrocatalytic activities. The Ni₂P@BP shows improved Li diffusion kinetics (e.g., the Li ions diffusion coefficient increases from 1.14 × 10^–14 cm² s^–1 for pure BP nanosheets to 8.02 × 10^–13 cm² s^–1 for Ni₂P@BP). In addition, the Ni₂P@BP electrode sustains hydrogen production with almost unchanged activity over 3000 cycles, which indicates its good chemical stability when operating under strong reducing environment.