Coupling abundant active sites and an ultra-short ion diffusion path: R–VO ₂ /carbon nanotube composite microspheres boosted the performance of aqueous ammonium-ion batteries

R–VO 2 /CNTs composite microspheres was successfully prepared via ultrasonic atomization deposition exhibit more active sites and shorter ion diffusion paths than R–VO 2 microspheres, demonstrating superior electrochemical performance.