Abstract: Flexible free standing tin oxide(SnO₂) nanoparticles with different particle size/graphene sandwich paper electrodes were fabricated via a simple filtration method. The influence of SnO₂ particle size on electrochemical performances was investigated. The best electrochemical performances, including reversible specific capacity, cycling stability and rate capability, can be obtained when the particle size of thenanoparticles is at 6 nm,far superior to those of pristine SnO₂ and the corresponding composites composed of larger or smaller particles than optimum.