Method for preparing nano-copper powder

A method for preparing nano-copper powder, comprising:

• (1) providing a dispersion solution, the dispersion solution contains at least one copper salt precursor and at least one disperser, the disperser is dissoluble in both water and weak solvents, and is an acrylic modified polyurethane disperser;
• (2) providing a reducer dispersion solution, the reducer dispersion solution contains at least one reducer, the reducer is organic borane, the organic borane is one or more selected from the group consisting of triethyl borane and pinacolborane;
• (3) contacting the reducer dispersion solution with the dispersion solution provided by step (1) in a condition enough to reduce the copper salt precursor by the reducer into elementary copper;
• (4) separating copper nano-particles from reaction solution obtained by step (3), and drying separated copper nano-particles by spray drying, so as to obtain the nano-copper powder;
• wherein the dispersion medium in the dispersion solution in step (1) and the dispersion medium in the reducer dispersion solution in step (2) is deionized water.