Metal Oxides Nanoparticles Encapsulated in 3D Porous Carbon Microspheres for High Performance Lithium Storage

Nanostructured metal oxides (e.g., ZnO, CoO, SnO₂) have been considered as alternative anode materials for next-generation of lithium-ion battery (LIB) because of their higher reversible capacities (500–1500 mAh g⁻¹) than conventional graphite of 372 mAh g⁻¹. However, the metal oxide particles suffers from fast capacity decay due to its poor electrical conductivity, limited ions transport kinetics, serious aggregation, and large volume expansion (> 200%) and contraction during the charge/discharge process. To address these issues, we synthesized novel 3D porous carbon microspheres (PCM) from low cost raw materials (i.e., sucrose) via a spray pyrolysis method, and developed a new architecture of metal oxides nanoparticles decorated into the PCM by a simple one-pot hydrothermal method. The developed metal oxide/PCM hybrids (e.g., SnO₂@PCM, ZnO-CoO@PCM) demonstrated a high reversible capacity, good rate performance, and excellent cycling stability. The superior electrochemical performance is because (1) the continuous and large surface area carbon framework greatly enhanced the electrical conductivity and dispersion of metal oxides nanoparticles, (2) the porous structure with multi-modal pores could warrant good electrolyte diffusion and fast li-ion transport and provide sufficient space to buffer the large volume expansion of the metal oxides,and (3) the nano-sized metal oxide particles (less than 10 nm) are uniformly confined in the pores that avoid the strong aggregation. Our low-cost, eco-friendly and multifunctional materials may hold a significant promise for the construction of advanced electrodes for high performance energy storage devices.Furthermore, the 3D porous nanocomposite architecture could shed light on the design and synthesis of other advanced electrodes for energy conversion and storage.