Effect of mesoporous α-Fe2O3 nanoparticles doping on the structure and electrochemical hydrogen storage properties of Co0.9Cu0.1Si alloy

Mesoporous α-Fe2O3 nanoparticles were synthesized via a hydrothermal method using chitosan as the template. A Co0.9Cu0.1Si alloy was obtained by mechanical alloying method. Composites of Co0.9Cu0.1Si doped with different amounts of mesoporous α-Fe2O3 were prepared for the purpose of enhancing the electrochemical hydrogen storage performance of Co0.9Cu0.1Si alloy. The structural properties of the alloy and composites were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and N2 adsorption-desorption analysis. The electrochemical properties of the composite electrodes were tested using a three-electrode Ni/MH battery. The discharge capacities for the composites were higher than those for the Co0.9Cu0.1Si alloy and reached a maximum (605.9 mA h/g) for 5 wt.% content of α-Fe2O3. In addition, the composite alloys showed higher cycling stabilities, stronger high-rate dischargeability and lower charge-transfer resistance. The superior performance of the composite alloys is attributed to the mesoporous structure and large specific surface area of α-Fe2O3, which may be favorable for the transportation of hydrogen inside the alloy during the charge/discharge processes. Doping of mesoporous α-Fe2O3 nanoparticles on the Co0.9Cu0.1Si alloy provides an effective strategy in enhancing the electrochemical hydrogen storage properties of the alloy electrode.