Synergistic Nanoconfinement Synthesis of TiO₂/Mn₂O₃ Inverse Opals for High-Performance Lithium-Ion Battery Anodes with Suppressed Volume Expansion

Mn₂O₃ serves as a promising anode material for lithium-ion batteries (LIBs) due to its outstanding electrochemical performance. However, its practical application faces challenges from significant volume expansion during charge and discharge cycles, which leads to poor structural stability. In this study, inverse opal TiO₂/Mn₂O₃ nanocomposites are constructed by first synthesizing an inverse opal TiO₂ matrix as a nanoconfinement host and then introducing Mn₂O₃ nanoparticles into its pores via a postconfinement strategy. This unique nanoconfinement architecture effectively alleviates the volume variation of Mn₂O₃ during electrochemical cycling, thereby improving the cycling stability of the electrode. The porous structure also promotes pseudocapacitive lithium storage behavior, which enhances electrode performance and reversible capacity. Furthermore, the interconnected porous skeleton facilitates charge transport, reduces charge transfer resistance, and significantly accelerates lithium-ion diffusion. The best electrochemical performance is achieved at an optimal Mn₂O₃ filling ratio of 23.57%, where the composite electrode delivers a capacity of 588.7 mAh g^–1 after 100 cycles, demonstrating excellent cycling stability. The optimized nanocomposite also exhibits a low volume expansion rate of 133%, considerably lower than that of pure Mn₂O₃ (322%). Overall, this innovative nanostructural design strategy shows great potential for developing high-performance Mn₂O₃-based anodes, paving the way for advanced LIBs in the future.