Long-Lasting Zinc–Iodine Batteries with Ultrahigh Areal Capacity and Boosted Rate Capability Enabled by Nickel Single-Atom Electrocatalysts

Abstract

Zinc–iodine (Zn–I2) batteries have garnered significant attention for their high energy density, low cost, and inherent safety. However, several challenges, including polyiodide dissolution and shuttling, sluggish iodine redox kinetics, and low electrical conductivity, limit their practical applications. Herein, we designed a highly efficient electrocatalyst for Zn–I2 batteries by uniformly dispersing Ni single atoms (NiSAs) on hierarchical porous carbon skeletons (NiSAs-HPC). In situ Raman analysis revealed that the conversion of soluble polyiodides (I3 – and I5 –) was significantly accelerated using NiSAs-HPC because of the remarkable electrocatalytic activity of NiSAs. The resulting Zn–I2 batteries with NiSAs-HPC/I2 cathodes delivered exceptional rate capability (121 mAh g–1 at 50 C), and ultralong cyclic stability (over 40 000 cycles at 50 C). Even under 11.6 mg cm–2 iodine, Zn–I2 batteries still exhibited an impressive cyclic stability with a capacity retention of 93.4% and 141 mAh g–1 after 10 000 cycles at 10 C.

Single atom catalysts for triiodide adsorption and fast conversion to boost the performance of aqueous zinc–iodine batteries

“…Recently, SANi and SAFe were investigated to determine if these catalysts could boost the performance of Zn–I 2 batteries. 33,34 However, in these studies, SACs were randomly selected, and the catalytic and adsorption behaviour of different SACs were not investigated. It remains challenging to search for appropriate SACs to suppress the ShE in Zn–I 2 batteries because of the current poor understanding of the interaction between SACs and iodine species.…”

Deploying Cationic Cellulose Nanofiber Confinement to Enable High Iodine Loadings Towards High Energy and High‐Temperature Zn‐I2 Battery

“…The ex situ Raman spectra of the cCNF/AC@I 2 cathode at different charging/ discharging states were displayed in Figure 5d, in which the peak located at 108.1 cm À 1 and 154.9 cm À 1 were assigned to I 3 À and I 5 À , respectively. [36,37] The disappearance of these peaks at the fully charged state also validated the reversible 5e, the peaks of both AC@I 2 and cCNF/AC@I 2 cathodes associated with I 3 À gradually intensified during the discharging process, testifying the dissolution of the I 3 À into the electrolyte, which would result in the capacity decay. [7b,26] Impressively, the cCNF/AC@I 2 cathode exhibits significantly weaker peak intensity than the AC@I 2 cathode throughout the discharging process, further demonstrating the efficiency of the cCNF in quelling the polyiodide shuttle effect.…”

Metal–iodine batteries: achievements, challenges, and future

“…Currently, investigations are focusing on Fe and Ni single atoms in Zn–I 2 batteries, both exhibiting excellent catalytic properties. 181–183 For instance, when Fe single atoms were introduced into N-doped porous carbon, the resulting composite could achieve an outstanding redox kinetics, corresponding to a specific capacity of 158 mA h g −1 , even at 20C. 183 This can be attributed to the decreased energy barrier for the iodine conversion process facilitated by the Fe single atoms.…”

“…Similarly, Ma et al realized an ultra-high specific capacity of 121 mA h g −1 at 50C by dispersing Ni single atoms within hierarchical N-doped porous carbon, affirming the beneficial role of SACs in facilitating the iodine redox process. 181 On the other hand, transition metal oxides, sulfides, nitrides, and carbides are also regarded as excellent electrocatalysts. Among them, transition metal nitride (Fe 2 N) has been explored for use as an electrocatalyst in Zn–I 2 batteries due to its favorable electronic conductivity and intrinsic catalytic activity.…”