Study of internal electric field and interface bonding engineered heterojunction for high stability lithium-ion battery anode

In this paper, SnO₂/Ni₂SnO₄ heterojunctions were grown on NF by a simple secondary hydrothermal method. DFT-based calculations show that the SnO₂/Ni₂SnO₄ heterojunction has excellent thermal stability with a low band gap (1.7 eV) and Li⁺ diffusion barrier (0.822 eV), which is attributed to the generation of an internal electric field that promotes carrier transport. Electrochemical tests showed that the initial capacity of SnO₂/Ni₂SnO₄/NF was 1401 mAh g⁻¹, and its capacity was 970 mAh g⁻¹ after 200 charge/discharge cycles, which is attributed to metal-oxygen bonds at the interface and a special microsphere structure to improve the stability of the materials. In addition, the electrochemical behavior of SnO₂/Ni₂SnO₄/NF is dominated by capacitive behavior, resulting in excellent rate performance. The synthesis of SnO₂/Ni₂SnO₄/NF provides a reference for designing other heterojunctions anode materials.