Fabrication of a flexible current collector for lithium ion batteries by inkjet printing

A novel chemical process has been developed to formulate injectable nickel ink for conductive film. This chemical method has the ability to remove the oxidation on nickel nano-particle surfaces during ink fabrication; the nickel ions, which are produced during chemical etching, will be reduced and bridged among original nano-nickel particles in the following thermal sintering process at 350^◦C. X-ray diffraction results exhibit that the final nickel film has no significant composition change by this chemical method and that oxidation has been effectively removed. Scanning electron microscopy images show that this chemical process reduces nickel oxides into nickel and that the reduced nickel sticks on the original nickel particle surface acting as a “bridge” connecting each particle. So solid diffusion can be triggered easily among bridged nickel particles and sintered at relatively low temperatures. The resistivity of printed film is to 5 × 10⁻⁶ Ω ·m which is 71-times that of bulk nickel. The fabricated conductive nickel thin film has been applied on lithium ion batteries as a current collector for cathode and anode and shows good corrosion resistance and stability.