Puguang Peng, Zhonglin Wang, Di Wei
In nature, iontronic power generation often arises from complex mixtures of monovalent and multivalent ions, exemplified by osmotic power between seawater and river water. In contrast, most laboratory studies have relied on single-ion systems, overlooking the intricate interplay and additional free energy associated with multi-ion environments. Efficiently harvesting energy from such multi-ionic systems remains challenging due to strong ion-ion interactions, the inherent trade-off between ionic selectivity and permeability, and the limited efficiency of multi-ionic-electronic coupling at interfaces. Recent advances in iontronics offer new pathways to overcome these barriers by modulating multi-ionic dynamics through nanofluidic channel design, interface engineering, and external-field regulation. These approaches enable selective transport, cooperative migration, and dynamic coupling among diverse ions, thereby enhancing energy conversion efficiency and device stability. Looking ahead, the rational control of multi-ion interactions and transport dynamics may unlock a new generation of high-performance iontronic power sources rooted in natural multi-ionic systems.