Electrochemical Interaction of Sn-Containing MAX Phase (Nb₂SnC) with Li-Ions

In this Letter, we report on the interaction of Nb2SnC ternary transition metal carbide (MAX phase) with Li ions. Because of the presence of Sn layers, which can undergo alloying reaction with Li, this material may be promising for energy storage. Contrary to most electrodes, the performance of this material improves along with the cycle number; specifically, the capacity increases gradually from 87 to 150 mAh g–1 at a current density of 500 mA g–1 during 600 charge/discharge cycles. Postcycling study suggests that the alloying reaction makes the material break into smaller particles, increasing capacity. Because Nb2SnC is just one of many MAX phases, this work lays the foundation for exploration of the MAX phases in lithium-ion or other batteries.