In situ synthesis of SnO2 nanoparticles encapsulated in micro/mesoporous carbon foam as a high-performance anode material for lithium ion batteries

SnO2 has high capacity but poor cycling stability for Li-ion batteries due to pulverization and aggregation. Herein, we tackle these two challenges by uniformly dispersing carbon coated nanoSnO(2) into a micro-sized porous carbon matrix to form a nano-SnO2/C composite anode using a facile and scalable in situ synthesis strategy. The SnO2@C nanocomposite exhibits a capacity of 640 mA h g(-1) at 500 mA g(-1) in the initial 150 cycles and then increases to 720 mA h g(-1) and maintains this capacity for 420 cycles. The superior electrochemical performance with long cycle lifetimes of the carbon foam-SnO2 nanocomposites could be attributed to their unique carbon microstructures: the network of carbon sheets provides favorable electron transport, while the interconnected micro-/mesopores can serve as the effective channels of lithium ion transport, thereby supplying short lithium ion diffusion pathways. Meanwhile, these pores surrounding the active species of nanoSnO(2) along with flexible carbon nanosheets can accommodate the severe volume variations during prolonged electrochemical cycling and mitigate the Sn aggregation. The present study provides a large-scale synthesis route to synthesize SnO2-based anode materials with superior electrochemical performance for lithium ion batteries.