Porous MgO–CaO–SnO_x nanocubes (crystalline SnO_x and amorphous MgO/CaO) were synthesized to implant firmly and uniformly onto in situ formed carbon paper by a facile route including a template-free growth process and calcining treatment. Low-cost filter paper was used to realize the part implantation of cubes as well as a source of carbon paper. The mechanistic analysis demonstrates that Mg²⁺/Ca²⁺ ions and ammonium hydroxide played important roles in the formation of the cubic phase precursor. This MgO–CaO–SnO_x-nanocubes/carbon paper could be directly applied as a binder-free film electrode for lithium-ion batteries eliminating conventional electrode fabrication processes, and an average capacity contribution of ∼719 mA h g⁻¹ for MgO–CaO–SnO_x nanocubes through 40 cycles was achieved. The facile synthesis strategy combines the material synthesis, dispersion and electrode fabrication, which further opens a new avenue for the application of nano-architectures in energy storage.