Synergistic Nanoconfinement Synthesis of TiO ₂ /Mn ₂ O ₃ 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.