Conductive polymer networks: enabling high-performance zinc-ion batteries via dual-ion storage mechanism and structural suppression
Hanyu Wen, Yaowen Shi, Bosi Yin, Haokun Wen, Hui Li, Yali Yao, Siwen Zhang, Tianyi Ma
Abstract
Adaptive adjustment of layered metal oxide structures is the key to achieving high energy density in reversible zinc-ion batteries. However, as a transition metal oxide, vanadium-based cathode materials often have problems such as poor cycle stability and low energy storage capacity due to their poor conductivity and high solubility. Here, we constructed a covalent polymer network composed of polyaniline (PANI) in the layered structure of V 3 O 7 ⋅H 2 O (HVO). Through the construction of a conjugated polymer network, not only expands the layer spacing but also enhances the electron utilization rate in the protonation process of PANI, and the local charge accumulation in the redox process is effectively reduced. In addition, the interaction forces between PANI and HVO, including covalent bonds and hydrogen bonds, effectively inhibited the structural collapse of layered metal oxides and the dissolution of active substances alleviated the stress induced by ion intercalation. Finally, during the protonation process of polyaniline, the unique Zn 2+ /H + co-intercalation mechanism is concurrently achieved through synchronized H + intercalation/deintercalation dynamics, harmonized with the co-embedding of H + and Zn 2+ within the HVO framework. This collaborative energy storage, with PANI serving as an additional cathode material for zinc ion accumulation, achieves good cycle stability and a high specific capacity of 546 mAh g −1 at 0.1 A g −1 current density, significantly improving the battery’s energy storage performance. This work is of great significance to elucidate the charge storage mechanism and design organic–inorganic cooperative energy storage materials for high-performance zinc-ion batteries.