Abstract Iron oxalate/graphene sheet (FeC2O4/Gs) composites with different crystal polymorphs were prepared through simple solvothermal reaction by controlling synthesis temperature. The effect of crystal structure on the morphology and the electrochemical performance was investigated. The results show that the structure and morphology are strikingly different in both phases. The β-FeC2O4·2H2O/Gs is composed with irregular shaped of nanometer sized rod and sheet particles. In contrast, the composite of α phase is the micron polygonal prism structure which is due to the reordering of hydrogen bonds between inter layer, resulting in excellent electrochemical performance: 916.49 mAh g−1 for the reversible specific capacity, a retention of 66.9% after 50 cycles and nearly 550 mAh g−1 after 200 cycles at 1 C. This work provides a new way for oxalate-based anode materials to modify initial irreversible capacity and improve capacity retention.

中文翻译：

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不同晶型草酸铁/石墨烯片复合材料的形貌和电化学性能研究

摘要 通过控制合成温度，通过简单的溶剂热反应制备了不同晶型的草酸铁/石墨烯片(FeC2O4/Gs)复合材料。研究了晶体结构对形貌和电化学性能的影响。结果表明，两相的结构和形貌明显不同。β-FeC2O4·2H2O/Gs由不规则形状的纳米棒状和片状颗粒组成。相比之下，α相的复合物是微米多角棱柱结构，这是由于层间氢键的重新排列，导致优异的电化学性能：可逆比容量为916.49 mAh g-1，保留66.9% 50 次循环，1 C 下 200 次循环后接近 550 mAh g-1。