The practical deployment of zinc (Zn) metal anodes is severely hindered by uncontrolled dendrite growth and parasitic side reactions. Although organic additives can alleviate these issues, the fundamental relationship between their molecular structure and Zn deposition/stripping reversibility remains inadequately understood. Herein, a homologous series of amide additives is employed to establish the effect of molecular chain length on Zn reversibility. Complementary theoretical and experimental analyses reveal that alkyl chain extension increases the electron density of the carbonyl oxygen and strengthens Zn²⁺–amide coordination, thereby reorganizing the primary solvation sheath toward enhanced amide coordination. This regulation generates a dual effect: stronger coordination raises the nucleation overpotential and promotes dense, uniform Zn nucleation, while reduced interfacial water activity suppresses hydrogen evolution and corrosion reactions. Consequently, the optimized amides electrolyte delivers an average Coulombic efficiency of 99.6% and enables stable Zn||Zn cycling for over 900 h at 40 mA·cm⁻² and 25 mAh·cm⁻², corresponding to approximately 75.8% Zn utilization. Zn||VS₂ full cells retain 87.9% of their initial capacity after 1000 cycles. Notably, the same chain length-dependent enhancement is reproduced in carbonate additives, establishing molecular chain engineering as a transferable strategy for highly reversible Zn metal anodes.

Crystalline carbon nitride (CCN) has emerged as a highly promising semiconductor photocatalyst with unique properties, such as enhanced charge migration rate, reduced carrier recombination probability, narrow band gap and improved light-harvesting efficiency, which are suitable for a wide range of applications in solar-to-chemical conversion, energy storage, therapeutic and environmental pollution degradation. In the past few years, there has been an increasing number of reviews on CCN materials. However, most of these reviews mainly focus on synthesis methods, modification and applications, with less emphasis on the relationship between structures and properties, as well as on in-depth exploration of the crystalline structure. The electronic instability of CCN presents challenges for conventional characterization techniques to directly and thoroughly investigate the relationship between its intrinsic atom structure and photocatalytic performance. This mini-review not only highlights the progress in CCN-based photocatalysts, with a focus on molten-salt synthesis (including solid-salt-induced crystallization), but also emphasizes the atomic structure characterization by specifically introducing the differential phase contrast (DPC) scanning transmission electron microscopy (STEM) technique, which is essential for enhancing our understanding of the crystal structure and photocatalytic mechanisms of CCNs. Additionally, the review outlines the photocatalytic performance and puts forward potential challenges on CCN studies. This review will provide a clearer understanding of the relationship in developing precise customization strategies for CCN materials and ultimately explain the regularity and specificity of the enhanced performance in targeted photocatalytic systems.