Constructing binder-free Bi2O3@nitrogen-doped carbon nanotubes aerogel cathodes to boost polyiodide conversion kinetics by Bi-N bonds

Developing renewable green energy is one of key approaches to achieve dual carbon goals, which is supported by high-efficiency energy storage technologies. Aqueous Zn-I 2 batteries (AZIBs) are quite promising grid energy storage systems due to their intrinsic safety and low cost, but are plagued by polyiodide shuttling and sluggish conversion kinetics. To tackle the issues, a binder-free Bi 2 O 3 @N-CNTs aerogel electrode with hierarchical pore structure has been developed, featured by Bi 2 O 3 nanoparticles embedded in the N-doped CNTs matrix. Removing of polymer binder not only reduces the inactive component in the electrode but also avoids covering active sites. Notably, polyiodide affinity and catalytic capability of novel Bi 2 O 3 electrocatalyst can be enhanced significantly via the formation of Bi–N bonds, which has been demonstrated by the X-ray photoelectron spectroscopy and systematic electrochemical tests. The resultant AZIB demonstrates superior cycling stability, maintaining a capacity of 148.7 mA·h·g −1 after 5,000 cycles with a high capacity retention of 87.1%. Specially, the high-loading pouch cell can also deliver a stable capacity of 2 mA·h over 40 cycles with an areal loading of 10 mg·cm −2 , highlighting the practicality of the Bi 2 O 3 @N-CNTs aerogel electrode.