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

Abstract

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 nanoSnO₂ 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 nanoSnO₂ 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.