Supercapacitors with the advantages of high power density and fast discharging rate have full applications in energy storage. However, the low energy density restricts their development. Conventional methods for improving energy density are mainly confined to doping atoms and hybridizing with other active materials. Herein, a Co₃O₄/g‐C₃N₄ p–n junction with excellent capacity is developed and its application in an all‐solid‐state flexible device is demonstrated, whose capacity and energy density are considerably enhanced by simulated solar light irradiation. Under photoirradiation, the capacity is increased by 70.6% at the maximum current density of 26.6 mA cm⁻² and a power density of 16.0 kW kg⁻¹. The energy density is enhanced from 7.5 to 12.9 Wh kg⁻¹ with photoirradiation. The maximum energy density reaches 16.4 Wh kg⁻¹ at a power density of 6.4 kW kg⁻¹. It is uncovered that the lattice distortion of Co₃O₄, reduces defects of g‐C₃N₄, and the facilitated photo‐generated charge separation by the Co₃O₄/g‐C₃N₄ p–n junction all make contributions to the promoted electrochemical storage performance. This work may provide a new strategy to enhance the energy density of supercapacitors and expand the application range of photocatalytic materials.

中文翻译：

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光催化辅助Co3O4/g-C3N4 p-n结全固态超级电容器：储能与光催化之间的桥梁

超级电容器具有功率密度高、放电速率快等优点，在储能领域得到充分应用。然而能量密度低限制了它们的发展。传统提高能量密度的方法主要局限于掺杂原子和与其他活性材料杂化。本文开发了一种具有优异容量的Co ₃ O ₄ /g-C ₃ N ₄ p-n结，并展示了其在全固态柔性器件中的应用，通过模拟太阳光，其容量和能量密度显着提高辐照。^{在光照射下，在最大电流密度26.6 mA cm -2}和功率密度16.0 kW kg ^-1时，容量增加了70.6% 。通过光照射，能量密度从7.5 Wh kg -1 提高到12.9 Wh kg ^-1。在功率密度为6.4kW kg ^-1时，最大能量密度达到16.4 Wh kg ^-1。研究发现，Co ₃ O ₄的晶格畸变、减少g-C ₃ N _{4的缺陷以及Co 3} O ₄ /g-C ₃ N ₄ p-n结促进的光生电荷分离都使得对促进电化学存储性能的贡献。这项工作可能为提高超级电容器的能量密度和扩大光催化材料的应用范围提供新的策略。