Enhanced reaction kinetics and structure integrity of Cu/F co-doped SnO₂@C composite for high-performance lithium-ion batteries

For SnO₂ anode materials, strategies such as nanosizing, compositing with high-conductivity materials and chemical element doping are often employed to improve their lithium storage performance. Herein, an effective strategy is proposed to prepare coral-like hollow porous nanostructured Cu/F co-doped SnO₂ by hydrothermal ion doping to enhance the diffusion kinetic performance of lithium ions from the inside, while the external amorphous carbon layer is coated by glucose carbonisation to improve the electrical conductivity on the one hand, and to further inhibit the huge volume expansion on the other hand. Through this internal and external strategy, the Cu/F co-doped SnO₂@C electrode with high capacity, better rate capability and cycling performance is obtained, which has a specific capacity of 1037 mAh g⁻¹ after 100 cycles at 0.1 A/g, with a capacity retention rate of 100.5 %. Furthermore, the Cu/F co-doped SnO₂@C anode offers long-term cycling stability even at 2 A/g, with a reversible specific capacity of up to 612 mAh g⁻¹ after 1200 cycles. To further explore the practical applications, the Cu/F co-doped SnO₂@C anode is also coupled with Li₂CoO₂ cathode and assembled into full cells, which show good energy storage characteristics and potential for practical applications (specific capacity of 704 mAh g⁻¹ after 50 cycles at 0.2 A/g). The kinetic mechanism of lithium storage is investigated by theoretical calculations and experiments, indicating that the constructed LiF/Li₂O heterogeneous grain boundary is more conducive to lithium ion transport and improves the performance of lithium ion diffusion kinetics.