Electrochemical deposition (ED) dates back to Faraday and is a well-established approach for producing coatings. This review summarizes unconventional ED approaches, where nanostructured films are deposited, starting with nanomaterials as building blocks, instead of molecular or ionic species. This “nano to nano” deposition concept has a significant advantage of directly transferring nano-objects from the dispersion to the coating, which maintains their unique nanostructures. It is achieved via destabilizing the nano-objects in the dispersions by applying electrochemical potential or current, which diminishes the interparticle repulsion through two different mechanisms: (a) Direct redox induced deposition; (b) Indirect pH and ionic strength induced deposition. With electrochemical reactions as a driving force, the deposition process is selective to conductive and electrochemically active substrates and can be manipulated by potential/current and time, yielding films with thickness from nanometers to a few microns. Notably, electrochemically inactive and even non-conductive nanomaterials may also be electrochemically deposited via the “nano to nano” approach using an indirect mechanism. Challenges and prospects are also discussed.
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