All‐Inorganic Cesium Zinc Halides as Ultra‐Stable Lead‐Free Perovskite Electrodes for Li‐Ion Batteries

Halide perovskites have recently gained attention for use as electrode materials in lithium‐ion batteries. However, lead halide perovskites cannot withstand the harsh chemical environment in a standard lithium battery and tend to degrade after a few cycles. Here, we investigated a class of lead‐free all‐inorganic zinc perovskite halides (Cs 2 ZnX 4 ; X = Cl or Br) as the Li + storage materials in the lithium‐ion batteries (LIB). These materials can be synthesized by a facile mechanochemical method and exhibit a high lithium storage capacity with impressive rate performance and stability. We further improved the performance by evaporating a thin layer of C 60 on the pristine electrode, enabling faster Li + ion transport. We found that the C 60 layer prevents direct contact between the electrode and electrolyte, thereby deterring side reactions and providing superior mechanical stability. The Cs 2 ZnCl 4 LIB achieved an initial discharge capacity of 349 mAh g −1 and a reversible capacity of 98 mAh g −1 after 100‐cycles, with continuing functionality up to 500 cycles. Unlike traditional perovskites, these zinc‐based materials may lead to high performance, non‐toxic Li‐ion intercalation layers that are both stable and efficient.