Abstract Hybrid inorganic–organic nanoarchitectures are created by self-limiting electrodeposition of ultrathin poly(phenylene oxide) (PPO) coatings on high surface area (>200 m 2 g −1), mesoporous sol–gel-derived MnO 2. Scanning electron microscopy images confirm that the polymer film coats the porous surface without completely covering over or occluding the large-scale porosity of the oxide nanoarchitecture. X-ray photoelectron spectroscopic measurements show C1s and O1s photoelectron peaks consistent with the reported PPO structure. Cyclic voltammetry demonstrates that the encapsulated MnO 2 undergoes reversible Li-ion insertion/de-insertion reactions where the Li + ions are supplied through the polymer coating from an acetonitrile electrolyte; the polymer coating does not affect the nature of insertion into the oxide. These hybrid systems assemble inorganic and organic components on the nanoscale and offer routes to new architectures with expanded functionality and enhanced electrochemical performance for energy-storage applications.