All-inorganic lead halide perovskite nanohexagons for high performance air-stable lithium batteries

Abstract

All-inorganic Cs₄PbBr₆ perovskite nanohexagons, pre-synthesized by a room temperature co-precipitation method, have been electrochemically investigated in a conventional aqueous electrolyte for potential application as an anode material in Li-ion batteries. The nanohexagons were uniformly deposited on ITO precoated glass substrate and subsequently annealed at ambient air to form a mechanically stable perovskite layer. These perovskite layers showed excellent performance during continuous Li-ion intercalation/deintercalation scans in an aqueous electrolyte, exhibiting a diffusion coefficient of 7.34 × 10⁻⁸ cm² s⁻¹, a specific discharge capacity of 377 mA h g⁻¹, a capacity retention of 75% and coulombic efficiency that deteriorated to 98% after 100 scans. A water-triggered transformation of the Cs₄PbBr₆ to the CsPb₂Br₅ was initially observed followed by a reversible Li intercalation/deintercalation in the CsPb₂Br₅ structure for 40 consecutive scans. Following this period, an irreversible conversion reaction of CsPb₂Br₅ to CsBr and PbBr₂ took place. The excellent electrochemical performance observed is promising towards the potential application of all-inorganic perovskite nanocrystals for air-stable, lithium storage applications.