【目的】钾离子电池具有低成本和能量密度高等优势,成为锂离子电池潜在的替代品,受到人们广泛的关注。但是,由于缺乏高比容量、循环寿命长的正极材料,使得这类新型电池的发展受到了限制。【方法】采用水热前驱体法、溶胶凝胶法和草酸盐共沉淀法制备了新型钾离子电池正极材料P3型K0.5MnO2.【结论】结果表明与其他两种方法相比,水热前驱体法制备的K0.5MnO2(H-K0.5MnO2)具有粗糙的表面和较多的内部孔隙,有利于电子的传递和提供更多的活性位点。H-K0.5MnO2电极在电流密度20mA/g下,首周放电比容量最高,达到85mAh/g,60周循环后电极片的XRD和EIS测试结果表明在重复的脱嵌K+后,H-K0.5MnO2仍保持最稳定的结构以及最小的电荷传递阻抗。储钾性能研究的结果表明在高倍率下H-K0.5MnO2赝电容占比最高,从而能够实现快速的可逆充放电。

【Purposes】 K-ion batteries (KIBs) have attracted considerable attention as a poten-tial alternative to Li-ion batteries because of their low cost and high energy density. However, the development of KIBs has been severely limited by the lack of cathodes with high specific ca-pacity and good cycle performance. 【Methods】 In this research, P3-type K0.5MnO2 as a new cath-ode material for KIBs was prepared through hydrothermal method, sol-gel method, and oxalate co-precipitation method, separately. 【Conclustions】 It is shown that K0.5MnO2 synthesized through the hydrothermal precursor method (denoted as H-K0.5MnO2) has a rough surface and more internal pores, which are beneficial to electron transfer and can provide more active sites. At a specific current of 20 mA/g, H-K0.5MnO2 electrode can achieve the highest first discharge specific capacity of 85 mAh/g. XRD and EIS results of the H-K0.5MnO2 electrodes after 60 cycles demonstrate that H-K0.5MnO2 still maintains the most stable structure and has the smallest charge transfer resistance, leading to a desirable capacity retention. The potassium-ions storage properties indicate that the pseudo-capacitance accounts for the highest proportion in H-K0.5MnO2 at a high rate, enabling fast reversible charge-discharge.