This investigation reports the morphological and structural properties of ZnO doped with the Al, In and Ga elements and its utilization as redox material to improve the capacitance and energy density of graphene supercapacitors (SCs). All the ZnO nanoparticles doped with these elements presented a plate-like morphology with irregular edges and had hexagonal wurtzite phase. Moreover, the values of band gap were obtained for the ZnO nanoparticles and they are reduced with the order of: ZnO:Ga (3.2 eV)>ZnO:In (3.0 eV)>ZnO:Al (2.95 eV). The results of electrochemical characterization revealed that the graphene SCs made without ZnO presented a maximum capacitance and energy density of 97.2 F g⁻¹ and 19.4 Wh kg⁻¹, respectively. After the deposition of the Al, In or Ga-doped ZnO nanoparticles to the SC electrodes, the capacitance and energy density are enhanced by 22–193%. The maximum values of capacitance and energy density of 284.6 F g⁻¹ and 56.9 Wh kg⁻¹ were observed for the SC made with ZnO:Al. Moreover, the analysis by Raman and photoluminescence demonstrated the presence of Zinc interstitials, oxygen vacancy and oxygen interstitials defects, which served as redox centers for the charge storage in the solid state SCs. In general, this research confirmed that adding doped ZnO into the SCs is a good strategy to increment their performance, which is of interest for energy storage applications.

本研究报告了掺杂 Al、In 和 Ga 元素的 ZnO 的形态和结构特性，以及它作为氧化还原材料的用途，以提高石墨烯超级电容器 (SC) 的电容和能量密度。所有掺杂这些元素的ZnO纳米粒子均呈现出边缘不规则的板状形态，并具有六方纤锌矿相。此外，获得了 ZnO 纳米粒子的带隙值，它们按以下顺序减小：ZnO:Ga (3.2 eV)>ZnO:In (3.0 eV)>ZnO:Al (2.95 eV)。电化学表征结果表明，在没有 ZnO 的情况下制备的石墨烯 SCs 的最大电容和能量密度分别为 97.2 F g ^-1和 19.4 Wh kg ^-1， 分别。在将 Al、In 或 Ga 掺杂的 ZnO 纳米颗粒沉积到 SC 电极后，电容和能量密度提高了 22-193%。对于由 ZnO:Al 制成的 SC，观察到电容和能量密度的最大值为 284.6 F g ^-1和 56.9 Wh kg ^{-1 。}此外，拉曼和光致发光分析证明了锌间隙、氧空位和氧间隙缺陷的存在，它们充当了固态 SCs 中电荷存储的氧化还原中心。总的来说，这项研究证实，在 SCs 中添加掺杂的 ZnO 是提高其性能的好策略，这对储能应用很有意义。