Facile synthesis of tin dioxide-based high performance anodes for lithium ion batteries assisted by graphene gel

• Ultrasmall tin dioxide nanoparticles constrained in graphene gel: SnO2@GG.
• SnO2@GG composite is prepared by a facile one-pot strategy.
• The graphene framework provides large void space and good conductivity.
• This composite exhibits an excellent electrochemical performance.

Tin dioxide (SnO2) is an attractive material for anodes in energy storage devices, because it has four times the theoretical capacity of the prevalent anode material (graphite). The main obstacle hampers SnO2 from practical application is the pulverization problem caused by drastic volume change (∼300%) during lithium-ion insertion or extraction, which would lead to the loss of electrical conductivity, unstable solid-electrolyte interphase (SEI) formation and consequently severe capacity fading in the cycling. Here, we anchored the SnO2 nanocrystals into three dimensional graphene gel network to tackle this problem. As a result of the three dimensional (3-D) architecture, the huge volume change during cycling was tolerated by the large free space in this 3-D construction, resulting in a high capacity of 1090 mAh g−1 even after 200 cycles. What's more, at a higher current density 5 A g−1, a reversible capacity of about 491 mAh g−1 was achieved with this electrode.