Department of Applied Chemistry, College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, P. R. China.
Dalton Trans. 2019 Feb 12;48(7):2491-2504. doi: 10.1039/c8dt04974b.
K-doped FeOOH/Fe3O4 nanoparticles with a size of 100 nm were grown on stainless steel (SS) hydrothermally. The effect of the synthetic conditions on compositions, morphologies and electrochemical performances was discussed, and the possible synthetic mechanism was proposed. The obtained K-doped FeOOH/Fe3O4/SS demonstrated a superior specific capacity of 396 mA h g-1 (0.554 mA h cm-2) at 1 A g-1 in 2 M KOH, which is the largest value reported so far. And it was also much larger than those of K-doped and -undoped FeOOH/SS samples. Furthermore the sample manifested an increasing capacity during the cycling test, which was probably associated with the doping of K+ as well as the coexistence of Fe(ii) and Fe(iii) in the structure. Based on density functional theory (DFT), the effect of the K-doping on the electron conductivity of the sample was theoretically investigated. In addition, a Co-Mo-O/Ni3S2/Ni foam (NF)//K-doped FeOOH/Fe3O4/SS asymmetric supercapacitor was fabricated, which can deliver a high energy density of 74.38 W h kg-1 at a power density of 3.64 W kg-1.
K 掺杂的 FeOOH/Fe3O4 纳米粒子在不锈钢（SS）上通过水热法生长，尺寸为 100nm。讨论了合成条件对组成、形貌和电化学性能的影响，并提出了可能的合成机制。所得 K 掺杂的 FeOOH/Fe3O4/SS 在 2 M KOH 中以 1 A g-1 的电流密度表现出 396 mA h g-1（0.554 mA h cm-2）的优异比容量，这是迄今为止报道的最大值。而且，它也远大于 K 掺杂和未掺杂的 FeOOH/SS 样品。此外，该样品在循环测试中表现出容量增加，这可能与 K+的掺杂以及结构中 Fe(ii)和 Fe(iii)的共存有关。基于密度泛函理论（DFT），从理论上研究了 K 掺杂对样品电子电导率的影响。此外，还制备了 Co-Mo-O/Ni3S2/Ni 泡沫（NF）//K 掺杂的 FeOOH/Fe3O4/SS 非对称超级电容器，其在 3.64 W kg-1 的功率密度下可提供 74.38 W h kg-1 的高能量密度。
