Mechanochemical synthesis of Fe/Mn-based binary hexacyanoferrate for sodium-ion battery

In this work, a facile one-pot two-step mechanochemical technology is firstly developed to prepare Fe/Mn-based binary hexacyanoferrates (Na x (FeMn)[Fe(CN) 6 ] y , FeMnHCF)/carbon composites by coupling in-situ construction of the conductive network and solid-state reaction. It is found that construction of hierarchical conductive network is favorable to improve the rate performance and cycling stability, with an 80.5% capacity retention over 1000 cycles at 360 mA/g. Furthermore, the capacity attenuation and stabilization mechanisms are investigated by GITT, EIS , and ex-situ XRD . The capacity attenuation in the early stage can be attributed to the large charge transfer resistance, while in the latter stage the long cycling stability is ascribed to the solid solution reaction with the mitigated stress distortion during the desodiation/sodiation process. Overall, the proposed mechanochemical synthesis of Fe/Mn-based binary hexacyanoferrate shows great potential in environmental friendliness and cost-saving production as well as comprehensive product performance.