Abstract Graphene gels have attracted intense research due to their excellent gravimetric performances in supercapacitors. However, their low volumetric capacitance and cycling stability limit their practical application. In this work, three-dimensional (3D) reduced graphene aerogel (RGAs) with hierarchical porous and high electrical conductivity were synthesized via simple low temperature chemical reduction method using graphene oxide as precursor and L-cysteine as reducing and functional agent. The sample RGAs-8 that prepared after reduction for 8 h displayed the highest mass density, higher electrical conductivity and cross-linked porous structure. Electrochemical measurements showed that the gravimetric capacitance and the volumetric capacitance of RGAs-8 reached as high as 203.9 F g−1 and 293.6 F cm−3 at 0.5 A g−1 in 6 M KOH aqueous electrolyte, respectively. In particular, the capacitance of RGAs-8 showed no capacitance loss even after 300,000 charge/discharge cycles, clearly demonstrating a robust long-term stability.

中文翻译：

---

用于具有高体积电容和超长循环稳定性的高性能超级电容器的功能化石墨烯水凝胶的简便合成

摘要 石墨烯凝胶因其在超级电容器中优异的重量性能而引起了广泛的研究。然而，它们的低体积电容和循环稳定性限制了它们的实际应用。在这项工作中，使用氧化石墨烯作为前体，L-半胱氨酸作为还原和功能剂，通过简单的低温化学还原方法合成了具有分层多孔和高导电性的三维（3D）还原石墨烯气凝胶（RGA）。还原 8 h 后制备的样品 RGAs-8 显示出最高的质量密度、更高的电导率和交联的多孔结构。电化学测量表明，RGAs-8 的重量电容和体积电容在 0 时分别高达 203.9 F g-1 和 293.6 F cm-3。分别在 6 M KOH 水性电解质中 5 A g-1。特别是，即使在 300,000 次充电/放电循环后，RGAs-8 的电容也没有显示出电容损失，这清​​楚地表明了强大的长期稳定性。