Facile thiourea-assisted synthesis of SnO₂/SnS heterojunctions anchored on N/S co-doped graphene aerogel for high-performance sodium-ion battery anodes

This study presents a facile thiourea-assisted self-assembly freeze-thaw strategy to in situ construct SnO₂/SnS heterojunctions anchored on three-dimensional porous N/S co-doped graphene aerogel (SnO₂/SnS/NSGA) for high-performance sodium-ion battery anodes. By precisely controlling thiourea dosage, we achieved simultaneous modulation of the SnO₂/SnS heterojunction ratio, the graphene pore structure, and the levels of N/S doping. The optimized SnO₂/SnS/NSGA-2 composite exhibits exceptional electrochemical performance, delivering a reversible capacity of 501 mAh g⁻¹ after 300 cycles at 0.1 A g⁻¹ and maintaining 204 mAh g⁻¹ at 2 A g⁻¹ . Systematic characterization and kinetic analysis reveal that the synergistic effects between the SnO₂/SnS heterostructure and NSGA matrix enhance charge transfer kinetics and Na⁺ diffusion, while the 3D porous network accommodates volume changes. And the sodium storage mechanism dominated by the pseudocapacitor contributes to the material's remarkable rate capability. This work provides a green, scalable approach for designing heterojunction-based multifunctional composite materials. • One-step thiourea-assisted self-assembly synthesized SnO₂/SnS/NSGA composite. • Ultrafine SnO₂/SnS heterojunctions uniformly anchored on N/S-doped porous GA. • The material exhibited excellent electrical conductivity and charge transferability. • Composites showed enhanced rate capability and cycle stability.