Facile synthesis of ultrafine SnO₂ nanoparticles on graphene nanosheets via thermal decomposition of tin-octoate as anode for lithium ion batteries

We demonstrate a facile synthesis of ultrafine SnO₂ nanoparticles within graphene nanosheets (GNSs) via thermal decomposition of tin-octoate, in which tin-octoate is firstly blended with GNSs followed by annealing in air at a low temperature (350 °C) and a short time (1 h). As anode for lithium ion batteries, the SnO₂/GNSs displays superior cycle and rate performance, delivering reversible capacities of 803 and 682 mA h/g at current densities of 200 and 500 mA/g after 120 cycles, respectively, much higher than that of pure SnO₂ and GNSs counterparts (143 and 310 mA h/g at 500 mA/g after 120 cycles, respectively). The enhanced electrochemical performance is attributed to the ultrafine SnO₂ nanoparticle size and introduction of GNSs. GNSs prevent the aggregation of the ultrafine SnO₂ nanoparticles, which alleviate the stress and also provide more electrochemically active sites for lithium insertion and extraction. Moreover, GNSs with large specific surface area (~363 m²/g) act as a good electrical conductor which greatly improves the electrode conductivity and also an excellent buffer matrix to tolerate the severe volume changes originated from the Li-Sn alloying-dealloying. This work provides a straight-forward synthetic approach for the design of novel composite anode materials with superior electrochemical performance.