Sandwich-like Na0.23TiO2 nanobelt/Ti3C2 MXene composites from a scalable in situ transformation reaction for long-life high-rate lithium/sodium-ion batteries

Ti3C2 MXene-based composites are emerging two-dimensional (2D) layered materials promising in electrochemical energy storage devices such as rechargeable ion batteries and supercapacitors. However, scalable preparation of Ti3C2 MXene-based composites, especially, integrated with one-dimensional (1D) materials through a facile low-temperature strategy remains a considerable challenge. Herein, novel sandwich-like Na0.23TiO2/Ti3C2 composites made of 1D amorphous Na0.23TiO2 nanobelts growing on 2D Ti3C2 nanosheets have been prepared through a one-step scalable transformation reaction of Ti3C2 MXene. The sandwich-like Na0.23TiO2/Ti3C2 composites comprising of 1D ultrathin nanobelts, 2D conductive nanosheets and 3D sandwich-like architecture with electrically connecting interfaces inside can effectively relieve strain of the electrode upon cycling, facilitate carrier transport dynamics and protect aggregation of the electrode material, favorable for high-performance rechargeable batteries. As a result, when employed as anodes in Li/Na-ion batteries, the Na0.23TiO2/Ti3C2 electrodes exhibit superior long cycling stability (up to 4000 cycles at the high rates with respective capacity retention of over or nearly 100%), and remarkable rate capability. This work may open a new way for scalable synthesis of 2D layered MXene-based composites with desired architectures and properties for practical energy applications.