Ultrahigh-performance mesoporous ZnMn₂O₄ microspheres as anode materials for lithium-ion batteries and their in situ Raman investigation

Currently, lithium-ion batteries play a key role in energy storage; however, their applications are limited by their low energy density. Here, we design a facile method to prepare mesoporous ZnMn₂O₄ microspheres with ultrahigh rate performance and ultralong cycling properties by finely tuning the solution viscosity during synthesis. When the current density is raised to 2 A·g^-1, the discharge capacity is maintained at 879 mA·h·g^-1 after 500 cycles. The electrochemical properties of mesoporous ZnMn₂O₄ microspheres are better than that for most reported ZnMn₂O₄. To understand the electrochemical processes on the mesoporous ZnMn₂O₄ microspheres, in situ Raman spectroscopy is used to investigate the electrode surface. The results show that mesoporous ZnMn₂O₄ microspheres have a great potential as an alternative to commercial carbon anode materials.