Search

All‐inorganic CsPbIBr2 perovskite solar cells (PSCs) have recently gained growing attention as a promising template to solve the thermal instability of organic–inorganic PSCs. However, the relatively low device efficiency hinders its further development. Herein, highly efficient and stable CsPb0.7Sn0.3IBr2 compositional perovskite‐based inorganic PSCs are fabricated by introducing appropriate amount of multifunctional zinc oxalate (ZnOX). In addition to offset Pb and Sn vacancies through Zn2+ ions incorporation, the oxalate group can strongly interact with undercoordinated metal ions to regulate film crystallization, delivering perovskite film with low defect density, high crystallinity, and superior electronic properties. Correspondingly, the resulting device delivers a champion efficiency of 14.1%, which presents the highest reported efficiency for bromine‐rich inorganic PSCs thus far. More importantly, chemically reducing oxalate group can effectively suppress the notorious oxidation of Sn2+, leading to significant enhancement on air stability. [ABSTRACT FROM AUTHOR]

Renewable organic cathodes with abundant elements show promise for sustainable rechargeable batteries. Herein, for the first time, utilizing C60 fullerene as organic cathode for room‐temperature lithium‐ion battery is reported. The C60 cathode shows robust electrochemical performance preferably in ether‐based electrolyte. It delivers discharge capacity up to 120 mAh g−1 and specific energy exceeding 200 Wh kg−1 with high initial Coulombic efficiency of 91%. The as‐fabricated battery holds a capacity of 90 mAh g−1 after 50 cycles and showcases remarkable rate performance with 77 mAh g−1 retained at 500 mA g−1. Noteworthily, three couples of unusual flat voltage plateaus recur at ≈2.4, 1.7, and 1.5 V, respectively. Diffusion‐dominated three‐electron‐redox reactions are revealed by cyclic voltammogram and plateau capacities. Intriguingly, it is for the first time unveiled by in situ X‐ray diffraction (XRD) that the C60 cathode underwent three reversible phase transitions during lithiation/delithiation process, except for the initial discharge when irreversible polymerization in between C60 nanoclusters existed as suggested by the characteristic irreversible peak shifts in both in situ XRD pattern and in situ Raman spectra. Cs‐corrected transmission electron microscope corroborated these phase evolutions. Importantly, delithiation potentials derived from density‐functional‐theory simulation based on proposed phase structures qualitatively consists with experimental ones. [ABSTRACT FROM AUTHOR]