Among various types of anode materials, SnO₂ and Si-based materials are considered as the most promising anode candidates for next generation lithium ion batteries, due to their high theoretical specific capacity, low operating potential, natural abundance and environmental benignity. The main drawbacks of SnO₂ and Si-based anode materials are their large volume change during alloying/dealloying processes and low electrical conductivity. To solve these problems, in the present work, graphene oxide (GO) was introduced as the carbon matrix to ameliorate the poor electrical conductivity and buffer the large volume variation. Further modifications of SnO₂/GO and Si/GO nanocomposites have also been investigated.

The SnO₂/GO nanocomposites were synthesized by a facile hydrotherma...[ Read more ]

Among various types of anode materials, SnO₂ and Si-based materials are considered as the most promising anode candidates for next generation lithium ion batteries, due to their high theoretical specific capacity, low operating potential, natural abundance and environmental benignity. The main drawbacks of SnO₂ and Si-based anode materials are their large volume change during alloying/dealloying processes and low electrical conductivity. To solve these problems, in the present work, graphene oxide (GO) was introduced as the carbon matrix to ameliorate the poor electrical conductivity and buffer the large volume variation. Further modifications of SnO₂/GO and Si/GO nanocomposites have also been investigated.

The SnO₂/GO nanocomposites were synthesized by a facile hydrothermal method. The optimal conditions were found to be 12.5 wt. % of GO, 3 wt. % of vinylene carbonate (VC) and 48 hours hydrothermal reaction time. Under these conditions, SnO₂/GO nanocomposite delivers a reversible diacharging capacity of 891 mAh g^-1 with a Coulombic efficiency of 99% after 200 cycles at a current density of 800 mA g^-1.

The graphene oxide/polydopamine-coated Si nanocomposite (GO/PD-Si) was synthesized by a facile solution-based chemical method at room temperature. The nanocomposite with a PD coating layer of ~2 nm exhibits a high reversible specific capacity and excellent cycling stability (1074 mAh g^-1 after 300 cycles at 2100 mA g^-1) as anode material for lithium ion batteries. The PD coating layer can not only serve as a cushion to buffer the volume change of Si nanoparticles (NPs) during charge/discharge process and avoid direct contacts of Si NPs with liquid electrolyte, but also modify the surface property of Si NPs by introducing secondary amine groups, which can form amide groups with carboxyl groups and hydrogen bonds with hydroxyl groups on GO. These chemical interactions firmly anchor Si NPs to GO so that aggregations of Si NPs could be prevented. Moreover, the good lithium ion conductivity of PD is beneficial for rate performance.