Preparation and properties of SnO2/nitrogen-doped foamed carbon as anode materials for lithium ion batteries

The excellent lithium storage capacity of SnO2 makes it as a potential candidate for a new generation of lithium ion battery anodes. However, the large volume change (≥ 300%) produced during the deintercalation of lithium and the irreversible capacity generated by the conversion of SnO2 into Sn both inhibit the application of SnO2 on the negative electrode of lithium ion batteries. In order to solve these problems, SnO2 nanoparticles were grown in the vesicles or on the skeleton of the nitrogen-doped foamed carbon. Due to the high mechanical strength and elasticity of porous structure, the foamed carbon serves as a buffering agent and provides space for volume expansion generated during the process of deintercalation lithium, and thus promotes the cycle stability of electrode. Furthermore, the incorporation of N atoms increases the electrical conductivity and active sites of the foamed carbon, which further improves the electrochemical performance of the composites. Consequently, the obtained NC/SnO2 electrode has a specific high capacity exceeding 750 mAh/g after 100 cycles at a current density of 0.1 A/g. The specific capacity of the battery also reaches a high level (≥ 450 mAh/g) at high current charge and discharge(1.6 A/g).