A tellurium iodide perovskite structure enabling eleven-electron transfer in zinc ion batteries
Shixun Wang, Zhiquan Wei, Hu Hong, Xun Guo, Yiqiao Wang, Ze Chen, Dechao Zhang, Xiaoyu Zhang, Xuyong Yang, Chunyi Zhi
Abstract
The growing potential of low-dimensional metal-halide perovskites as conversion-type cathode materials is limited by electrochemically inert B-site cations, diminishing the battery capacity and energy density. Here, we design a benzyltriethylammonium tellurium iodide perovskite, (BzTEA)2TeI6, as the cathode material, enabling X- and B-site elements with highly reversible chalcogen- and halogen-related redox reactions, respectively. The engineered perovskite can confine active elements, alleviate the shuttle effect and promote the transfer of Cl- on its surface. This allows for the utilization of inert high-valent tellurium cations, eventually realizing a special eleven-electron transfer mode (Te6+/Te4+/Te2-, I+/I0/I-, and Cl0/Cl-) in suitable electrolytes. The Zn||(BzTEA)2TeI6 battery exhibited a high capacity of up to 473 mAh g-1Te/I and a large energy density of 577 Wh kg-1 Te/I at 0.5 A g-1, with capacity retention up to 82% after 500 cycles at 3 A g-1. The work sheds light on the design of high-energy batteries utilizing chalcogen-halide perovskite cathodes. Functional perovskites are promising energy storage materials but have received little attention. Here, authors report a tellurium iodide perovskite as a conversion-type material enabling eleven-electron redox in chloride containing aqueous electrolytes for zinc batteries.