JPS: Alkali-treated mesoporous Fe2O3 nanospheres/MXene for efficient lithium storage

In order to meet the rapid development of electric vehicles and portable electronic devices, lithium-ion batteries (LIB) have received widespread attention due to their high energy density and long service life. However, traditional graphite anodes cannot meet the growing demand for the next generation of LIB due to their low theoretical capacity (372 mAh/g). Therefore, exploring alternative anode materials with high capacity and cycle stability is essential for high-performance LIB.

Due to the large theoretical capacity of transition metal oxide (TMO), it is considered to be a promising negative electrode material in LIB. Among various TMOs, Fe2O3 has attracted widespread attention due to its low price, high theoretical capacity (1007 mA h/g), abundant reserves and non-toxicity. However, because of its poor electrical conductivity and serious changes in volume during lithium insertion/extraction, it leads to severe electrode damage and capacity loss. In order to overcome these problems, an effective strategy is to design TMOs with porous nanostructures. These porous nanoparticles can expand the contact interface between the electrode and the electrolyte and shorten the diffusion path of Li+ and electrons. More importantly, compared with large particles, porous nanostructures can alleviate the mechanical strain caused by repeated insertion/extraction of lithium.

Recently, Professor Fan Xiaobin and Professor Zhang Fengbao of Tianjin University published a research paper titled: Chemically-confined mesoporous γ-Fe2O3 nanospheres with Ti3C2Tx MXene via alkali treatment for enhanced lithium storage in the internationally renowned academic journal Journal of Power Sources. A simple strategy to manufacture a new type of γ-Fe2O3@Ti3C2Tx composite anode. As the -OH groups on Ti3C2Tx MXene and γ-Fe2O3 increase after alkali treatment, the mesoporous γ-Fe2O3 nanospheres can be easily deposited on Ti3C2Tx MXene through the formation of hydrogen bonds. Due to the conductive network and the strong synergistic coupling between Ti3C2Tx MXene and γ-Fe2O3, the prepared composite electrode has ultra-high reversible capacity and excellent cycle performance for LIB.



Figure 1. Synthetic schematic diagram of γ-Fe2O3@Ti3C2Tx composite


Figure 2. Physical characterization of Ti3C2Tx MXene, γ-Fe2O3 nanospheres and γ-Fe2O3@Ti3C2Tx composites.


Figure 3. Electrochemical performance of alkali-treated γ-Fe2O3@Ti3C2Tx


Figure 4. GITT curves of γ-Fe2O3/Ti3C2Tx and γ-Fe2O3@Ti3C2Tx electrode materials



In this paper, the alkali treatment strategy induces the formation of hydrogen bonds in situ to enhance the structure and interface stability of γ-Fe2O3@Ti3C2Tx composites. The unique conductive network structure formed by porous γ-Fe2O3 nanoclusters wrapped in Ti3C2Tx can not only effectively inhibit the volume change of γ-Fe2O3 nanoclusters, but also increase the conductivity of the electrode material, thereby ensuring the rapid movement of electrons. Therefore, the prepared γ-Fe2O3@Ti3C2Tx anode for LIB has excellent reversible capacity and cycle stability.
Literature link:
https://doi.org/10.1016/j.jpowsour.2021.229758.