Flexible zinc-ion batteries are promising power sources for wearable devices, but are hindered by zinc dendrite growth and limited cycle life, due to limited ionic transport and poor mechanical strength of electrolyte. This work presents a quasi-solid polymer gel (PG) electrolyte incorporating vertically aligned TiO₂ nanotubes (PATG) in a crosslinked polyvinyl alcohol matrix. PATG exhibited a compressive Young’s modulus of 56.7 MPa (vs. 21.9 MPa for PG), and especially much higher Zn²⁺ conductivity of 0.26 mS·cm^–1 than that of PG (0.056 mS∙cm^–1) and PPTG (0.074 mS·cm^–1) and larger Zn²⁺ transference number of 0.71 than those of PPTG film (0.61) and PG film (0.43). PATG electrolyte exhibited stable cycling performance over 3000 hours with low polarization and effectively suppressed zinc dendrite growth. In full batteries, Zn|PATG|α-MnO₂ delivered an initial capacity of 301.2 mAh·g^–1 at 0.1 C and 212.9 mAh·g^–1 at 0.5 C. Moreover, the flexible Zn|PATG|α-MnO₂ can work at different bending states and power electronic devices well. This work underscores that the directed ion-transport strategy is feasible and promising for safe, flexible, and durable zinc-ion batteries.

Water oxidation, an essential step in photosynthesis, has attracted intense research attention. Understanding the reaction pathways at the electrocatalyst/water interface is of great importance for the development of water oxidation catalysts. How the water is oxidized on the electrocatalyst surface by the positive charges is still an open question. This review summarizes current advances in studies on surface chemistry within the context of water oxidation, including the intermediates, reaction mechanisms, and their influences on the reaction kinetics. The Tafel analyses of some electrocatalysts and the rate-laws relative to charge consumption rates are also presented. Moreover, how the multiple charge transfer relies on the intermediate coverage and the accumulated charge numbers is outlined. Lastly, the intermediates and rate-determining steps on some water oxidation catalysts are discussed based on density functional theories.