Understanding the Entropy Decoupling for Ion Transport in Ordered Biomimetic Materials Toward Durable Aqueous Zinc Metal Batteries

Aqueous zinc metal batteries (AZMBs) have emerged as promising candidates for next-generation grid-scale electrochemical energy storage system, while their development is still challenged by zinc dendrite, gas production, and cathode degradation. Essentially, these issues mainly originate from disordered ion transport behaviors, which is regarded as entropy-induced side reactions. Entropy is typically decoupled into configurational entropy and excess entropy, which contributes to ionic and electronic distribution, respectively. Uniform ionic distribution with low configurational entropy can alleviate local by-products, while uneven electronic distribution with high excess entropy will improve reaction activity. However, these both aspects are difficult to be compatible in most cases. As an ideal carrier, the biomimetic materials with specific structure, leveraging the orderliness in morphological structure, molecular arrangement, and charge distribution, exhibit intrinsic advantages in modifying ionic behaviors. This review proposed the significant importance of entropy decoupling dominated by biomimetic materials for regulating ion behaviors. The entire process of ion transport, from electrolyte phase, interfacial electric double layer to electrode bulk phase, was discussed in detail from the perspective of entropy. Furthermore, the mechanism of entropy decoupling for achieving electrodes with both dynamics and stability is systematically analyzed. Finally, we provide outlooks on entropy-design concepts to enable durable AZMBs.