Hollow mesoporous hetero-ZnO/ZnMnO3 microspheres: template-free formation process and enhanced lithium storage capability towards Li-ion batteries as a competitive anode†

Hierarchical hollow porous structures have attracted enormous attention in the field of emerging electrochemical energy storage. Spinel ZnMnO₃ stands out from other metal oxide-based anodes thanks to its affordability, environmental friendliness, safety and large capacity. However, its modestly high-rate capability and cycling stability should be addressed for advanced Li-ion batteries (LIBs) via smartly engineering the electrode structures/components using simple strategies. In this contribution, we devised a scalable bottom-up methodology for the fabrication of hollow mesoporous ZnO/ZnMnO₃ (ZZMO) microspheres. The underlying template-free formation mechanism was rationally proposed. Benefiting from synergistic contributions from the bi-component-active ZnO–ZnMnO₃ hetero-structure at the nanoscale, hollow and mesoporosity, the resultant hollow ZZMO microspheres were endowed with a large reversible capacity of ～695 mA h g^?1 at 1 A g^?1, as well as stable cycling performance and a remarkable rate capability when utilized as a competitive anode for LIBs. Furthermore, the quantitative analysis demonstrates that the main faradaic capacitive contribution accounts for the outstanding lithium storage of the ZZMO anode. Promisingly, the LiNi_0.8Co_0.1Mn_0.1O₂//ZZMO full battery achieved a capacity of ～121.0 mA h g^?1 at 0.1 A g^?1, and energy density of ～188.6 W h kg^?1. More significantly, these results highlight that hollow porous ZZMO microspheres would be a promising low-cost anode for next-generation LIBs.