Renewable Biomass Flax-Derived Amorphous Carbon@SnO₂ with a Graphene Buffer Layer for Enhanced Li Storage Performance

SnO2 has been considered as a promising anode material for lithium-ion batteries due to its high theoretical specific capacity (782 mA h g–1), low price, eco-friendliness, and high natural abundance. However, SnO2-based anodes undergo a large volume change during lithiation and de-lithiation, leading to electrode cracking and high initial irreversible capacity. In this work, we report a renewable biomass flax-derived amorphous carbon@SnO2@graphene composite (PFC@SnO2@rGO). It exhibits great cycle stability and high capacity when employed as an anode material for Li-ion batteries. After 80 cycles at a current density of 100 mA g–1, the PFC@SnO2@rGO preserves a specific capacity of 1201.89 mA h g–1, about 1.64 times the capacity of PFC@SnO2. Also, it keeps an excellent specific capacity of 567.57 mA h g–1 after 500 cycles as the density is up to 2 A g–1. Amorphous carbon and the rGO (reduced graphene oxide) combine to form a unique 3D structure, which is primarily responsible for the material’s excellent electrochemical performance. This structure significantly suppresses the volume expansion of SnO2 particles and preserves the stability of the electrode structure. Amorphous carbon and rGO also offer strong conductivity to the electrode. The preparation strategy of C/metal oxides in this work can be displayed to design a low-cost electrode material for high-performance LIBs.