Coherent interface design in sintered GeO₂@Sn-MOF for high-performance lithium-ion anodes

Tin-based metal-organic frameworks (Sn-MOFs) are promising anode materials but suffer from structural instability and unstable solid-electrolyte interphase (SEI), leading to capacity fading and poor cycling performance. We employ coherent interface engineering to address these issues to develop sintered GeO₂@Sn-MOF with coherent grain boundaries, enhancing structural stability, lithium-ion transport, and cycling durability. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirm the formation of stable SnO₂/GeO₂ interfaces, mitigating volume expansion and improving mechanical integrity. Electrochemical tests show that the optimized Sn-3Ge composition achieves a high initial capacity of 1968 mAh g⁻¹ at 0.1 C, excellent rate capability of 480 mAh g⁻¹ at 5 C, and superior cycling stability, retaining 77 % capacity after 500 cycles at 1 A g⁻¹ . These findings highlight the role of coherent interfaces in enhancing lithium-ion diffusion and SEI stability, offering a promising strategy for high-performance lithium-ion battery anodes. • The GeO₂@Sn-MOF anode with coherent grain boundaries enhances stability, tackling SEI issues and limitations in Sn-based batteries. • The optimized Sn-3Ge anode achieves 1960 mAh g -1 at 0.1C, 480 mAh g -1 at 5C, and retains 77 % capacity after 500 cycles at 1 A g -1 . • DFT calculations reveal a synergistic Sn-Ge effect, enhancing electrochemical potential and Li-ion diffusion for superior Sn-3Ge anodes.