Intercalation and delamination of TiSnC with high lithium ion storage capacity.

Li-ion batteries attract great attention due to the rapidly increasing and urgent demand for high energy storage devices. MAX phase compounds, layered ternary transition metal carbides and/or nitrides show promise as candidate materials of electrodes for Li-ion batteries. However, the highest specific capacity reported up to now is relatively low (180 mA h g), preventing them from use in real applications. Exploring more MAX phase compounds with delaminated two-dimensional structure is an effective solution to increase the specific capacity. Herein, we report the reversible electrochemical intercalation of Li into TiSnC (MAX phase) nanosheets. Owing to the synergistic effects of intercalation and dimethyl sulfoxide (DMSO)-assisted exfoliation, TiSnC nanosheets are successfully obtained via sonication in DMSO. Moreover, when using as an anode of a Li-ion battery, TiSnC nanosheets exhibited an increasing specific capacity with cycling due to the exfoliation of TiSnC nanosheets via reversible Li-ion intercalation. After 1000 charge-discharge cycles, TiSnC nanosheets delivered a high specific capacity of 735 mA h g at a current density of 50 mA g, which is far better than other MAX phases, such as TiSC, TiSiC and NbSnC. The current work demonstrates the Li-ion storage potential and indicates a novel strategy for further intercalation and delamination of MAX phases.