Synergetic Optimization of Upper and Lower Surfaces of the SnO2 Electron Transport Layer for High-Performance n-i-p Perovskite Solar Cells.

The SnO2 electron transport layer (ETL) has been recognized as one of the most effective protocols for achieving high-efficiency perovskite solar cells (PSCs). To date, most research has primarily focused on the modification of the upper surface of SnO2 ETL films. The lower surface of the SnO2 film, which directly influences the film formation of solution-processed SnO2, is equally important but receives relatively less attention. Herein, we present a synergetic optimization approach involving the deposition of aluminum oxide (AlOx) via atomic layer deposition (ALD) as a buffer layer and the incorporation of rubidium acetate (RbAc) as an upper surface passivation additive. This process leads to a conformal coating of SnO2 nanoparticles, improved electrical performance, and higher-quality perovskite crystals. As a result, with this composite ETL film, the power conversion efficiency (PCE) reached 22.41 from 20.77%. Further modification with p-butyl iodide (BAI) on the perovskite upper surface increased the champion PCE to 23.32%, with a voltage loss of 0.41 V, ranking among the lowest values for the triple-cation mixed-halide perovskite absorber (1.58 eV). Importantly, the perovskite solar cells remained 87.30% of its initial performance after 14 days of aging and exhibited photostability under long-term UV (254 nm) illumination.

A comparison study of MnO2 and Mn2O3 as zinc-ion battery cathodes: an experimental and computational investigation.

The high specific capacity, low cost and environmental friendliness make manganese dioxide materials promising cathode materials for zinc-ion batteries (ZIBs). In order to understand the difference between the electrochemical behavior of manganese dioxide materials with different valence states, i.e., Mn(iii) and Mn(iv), we investigated and compared the electrochemical properties of pure MnO2 and Mn2O3 as ZIB cathodes via a combined experimental and computational approach. The MnO2 electrode showed a higher discharging capacity (270.4 mA h g-1 at 0.1 A g-1) and a superior rate performance (125.7 mA h g-1 at 3 A g-1) than the Mn2O3 electrode (188.2 mA h g-1 at 0.1 A g-1 and 87 mA h g-1 at 3 A g-1, respectively). The superior performance of the MnO2 electrode was ascribed to its higher specific surface area, higher electronic conductivity and lower diffusion barrier of Zn2+ compared to the Mn2O3 electrode. This study provides a detailed picture of the diversity of manganese dioxide electrodes as ZIB cathodes.

A high-performance free-standing Zn anode for flexible zinc-ion batteries.

Zinc-ion batteries (ZIBs) have attracted significant attention owing to their high safety, high energy density, and low cost. ZIBs have been studied as a potential energy device for portable and flexible electronics. Here, a highly flexible free-standing Zn anode is fabricated using a simple spin-coating technique, and its application in ZIBs is demonstrated. The free-standing Zn anode precursor is formed by mixing Zn particles with carbon nanotubes and poly(vinylidene fluoride)-co-hexafluoropropylene (PVDF-HFP). The hexafluoropropylene group in PVDF-HFP improves the mechanical properties of the free-standing Zn anode, whereas the carbon nanotubes created percolation conduction in the composite electrode, leading to an increased electrical conductivity of the anode. Owing to the excellent electrical conductivity and high specific surface area of the free-standing Zn anode, ZIBs with high capacity, rate performance, and mechanical flexibility are achieved. The volumetric energy density of the ZIBs reaches 8.22 mW h cm-3 with a battery thickness of 0.4 mm. This work demonstrates that free-standing Zn anodes are promising anodes for flexible ZIBs.