ultra-clean nature-style graphical abstract, scientific schematic illustration, horizontal layout, pure white background, minimalist vector academic style, ultra-thin precise lines, low-saturation professional blue-gray color grading, clear hierarchical structure, no shadow, no texture, no noise, high scientific rigor. the central device is a reversible dual-function membrane energy unit, asymmetric dual-structure design. the left domain represents discharge operation mode, the right domain represents charge operation mode, with clear ion conduction direction marked inside the device. two completely closed independent liquid circulation loops surround the central cell. the upper closed loop represents liquid hydrogen carrier circulation system, marked with general reversible redox symbol lhc / lhc-h₂, equipped with circulating pump and directional flow arrows to realize reversible hydrogen storage and release. the lower closed loop represents liquid oxygen carrier circulation system, marked with general reversible redox symbol loc / loc-o₂, equipped with circulating pump and flow arrows to achieve reversible oxygen capture and release. the entire system realizes fully self-sufficient gas circulation without external gas input. faint minimalist deep-sea shadow silhouette in the background corner, subtly indicating extreme oxygen-free anoxic deep-sea working environment. only unified symbolic labels are used in the whole figure, no specific material names, no specific chemical formulas, maintaining universal structural description. a small amount of concise english functional annotation is retained to clarify charge/discharge reversible working mechanism. the overall style is neat, advanced, standardized, consistent with advanced energy materials / nature communications graphical abstract aesthetic standards.