Energy storage technology is particularly important for stabilizing smart grids for the future. All-solid-state energy storage remains a critical challenge for advancing energy storage systems. Carbon nitride conjugated polymers have the greatest development potential due to their special direct photogenerated charge storage behavior. We successfully fabricated an electrolyte-free, all-solid-state photo-supercapacitor based on carbon-rich carbon nitride, comprising a C-rich carbon nitride conjugated polymer (CPCN), TiO₂ nanocrystals, and fluorine-doped tin oxide (FTO) conductive glass. The device structure follows the configuration FTO//TiO₂//CPCN//TiO₂//FTO, where CPCN functions as the light-absorbing layer for photogenerated carrier generation and charge storage, while TiO₂ serves as both charge stabilization and transport material. Material morphology was characterized by scanning electron microscopy (SEM), and the composition was analyzed by element distribution map equipped with SEM. Photoelectrochemical performance and charge storage behavior were systematically evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) measurements, and electrochemical impedance spectroscopy (EIS). The optimal CPCN aging time, TiO₂ mesoporous film thickness and TiO₂/CPCN electrode area were found to make the photogenerated charge storage capacity of the single cell reach 380.1 C•g^-1. It was also found that the specific capacity of the battery was stable at a constant level between 350.7 C•g^-1 and 340.3 C•g^-1 when the electrode area exceeded 9 cm^-2. The energy management concept of the photo-supercapacitor to store photogenerated electrons first and then release them can avoid the problem of photoelectric conversion performance degradation caused by the increase in size like photovoltaic cells. In parallel mode, the photoelectric synergistic effect of CPCN can further reduce electron loss, and the photo charge storage capacity is significantly improved to 412.8 C•g^-1, and the performance does not decay with the increase in battery size. C-rich carbon nitride-based all-solid-state photo-supercapacitors use solar energy to achieve efficient, stable, safe, easy-to-control, low-carbon and environmentally friendly all-solid-state energy storage. The device has broad application prospects in the fields of solar energy management, visual energy storage equipment and self-powered sensors in smart grids.

Key words: C-rich carbon nitride, conjugated polymer, all-solid-state photo-supercapacitor, photogenerated charge storage, solar energy