镁电池正极材料V2O5微球的制备及电化学性能

Synthesis and electrochemical performance of V2O5 microspheres as cathode materials of rechargeable magnesium batteries

利用水热法合成了具有多级结构的V2O5,通过调节溶液pH值,探究了材料微观形貌的变化,并将材料制成极片,以纯镁为负极,0.25mol/LMg(AlCl2EtBu)2为电解液组装成镁离子电池进行测试。在不加酸的情况下,生成的V2O5样品是由纳米棒自组装微球堆积而成的,但其电化学性能较差,在50mA/g的电流密度下首圈放电比容量只有102.8mAh/g,经过30次循环后仅能保持在69.5mAh/g。而在酸性条件下(pH=2或3),制得的V2O5样品均呈现薄纳米片自组装形成的花状微球。在pH=3时,制得的V2O5首圈放电比容量可提高到113.7mAh/g,经过30次循环后仍保持在79.7mAh/g。这些电化学性能的提升,得益于在酸性条件下,生成的V2O5具备更高的比表面积和更为疏松多孔的结构。

Hierarchical V2O5 cathode materials with different morphologies were synthesized by hydrothermal route by adjusting solution pH.The electrochemical performance of the materials was tested with magnesium metal anode and 0.25 mol/L Mg(AlCl2EtBu)2/THF electrolyte.V2O5 microspheres self-assembled by nanorods were obtained without acid.At a current density of 50 mA/g,the initial discharge specific capacity was 102.8 mAh/g and decayed to 69.5 mAh/g after 30 cycles.Flower-like microspheres can be obtained under acidic conditions.The initial discharge specific capacity of the sample prepared when pH equals 3 could reach 113.7 mAh/g at the current density of 50 mA/g and maintained 79.7 mAh/g after 30 cycles.The improvement of electrochemical performance could be attributed to the porous structure with high specific surface area.