Building microcracked structure fibrous cathode coated by Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) for ultra-stable fiber-shaped aqueous zinc ions batteries

Attributing to the advantages of intrinsic safety, high energy density, and good omnidirectional flexibility, fiber-shaped aqueous zinc ions batteries (FAZIBs), serving as energy supply devices, have multitude applications in flexible and wearable electronic devices. However, the detachment of active materials caused by bending stress generated during flexing process limits their practical application severely. To address the above issue, an effective integrated strategy employing microcracked activated cobalt hydroxide [A-Co(OH)₂] cathode with protective coating of poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT:PSS) was proposed in this work to enhance the cyclic and bending performances of FAZIBs. The microcracked A-Co(OH)₂ cathode relieves stress concentration under bending conditions, while the PEDOT:PSS coating is responsible to maintain the structural integrity and prevents the detachment of A-Co(OH)₂. The FAZIBs based on a gel electrolyte achieved a high energy density (173.5 Wh·kg⁻¹) at a power density 90 W·kg⁻¹ and a bending durability (94.4 % capacity retention after 500 cycles) as a consequence of the synergistic effect of microcracked A-Co(OH)₂ cathode and the PEDOT:PSS coating. This work will offer a new approach for devising high-performance FAZIBs and promote the development of highly flexible and stable fiber-shaped batteries. © 2024 Elsevier Inc.