ACS Energy Letters 最新文献

The recent re-emergence of aqueous Zn–metal battery technologies, including Zn-ion and electrolytic stripping–plating chemistry, represents potentially viable batteries, particularly in terms of their manufacture–installation costs. However, many critical factors need to be addressed to ensure further advancements in these emerging Zn–metal technologies along with improving the existing Zn-based technologies, including alkaline Zn–MnO₂, Zn–Ni, and Zn–air batteries. Specifically, alkaline Zn–MnO₂ batteries face the challenge of complete consumption of the 2e^– with respect to MnO₂, while Zn–Ni batteries struggle in terms of the anode stability and the cost of cathodes. As such, research has yet to resolve the mildly acidic Zn–MnO₂ battery’s intricate diverse electrochemical mechanism(s), while the strong acidic–alkaline decoupled Zn–MnO₂ battery suffers from anode–cathode dissolutions. This Perspective provides the status of aqueous Zn–metal battery technologies and the factors associated with their practical developments along with our simulation of energy density calculations.

Phase stability under illumination is important for applications of halide perovskite semiconductors in both solar photovoltaics and light-emitting diodes (LEDs). We use hyperspectral photoluminescence microscopy to study compositional heterogeneity and its influence on the photostability of formamidinium (FA)-cesium (Cs) mixed-cation lead halide perovskites. We observe increased lateral photoluminescence heterogeneity of perovskite films made with higher Cs concentrations. We correlate photoluminescence maps with time-of-flight secondary ion mass spectrometry (ToF-SIMS) depth profiling and show that the redder-photoluminescence regions of the perovskite films are associated with vertical A-site segregation with Cs-rich compositions on top and FA-rich compositions underneath. X-ray diffraction and confocal Raman spectroscopy indicate the presence of nonphotoemissive δ-phase CsPbI_xBr_3–x in these regions of redder photoluminescence. Under illumination, these Cs-rich cluster regions undergo a faster degradation of their photoluminescence emission. These observations highlight the importance of local A-site compositional heterogeneities on the stability of halide perovskite semiconductors being studied for optoelectronics.

The membrane electrode assembly (MEA) electrolyzer stands out as the most practical design for CO₂ electrolysis. However, its compact configuration poses challenges in monitoring internal dynamic behaviors under real operating conditions. Here, we employ operando electrochemical impedance spectroscopy (EIS) testing and distribution of relaxation times (DRT) analysis to probe the complex charge-transfer and mass-transport processes within the MEA electrolyzer for CO₂ to CO conversion. By systematically varying assembly and electrolysis parameters, we successfully disentangle the parameter dependencies and identify specific processes in the DRT spectra. Furthermore, integrating DRT analysis with post-mortem characterizations, including scanning electron microscopy (SEM) and water contact angle measurements, reveals that the obstructed CO₂ mass transport is a significant factor contributing to performance failure in the stability test. These findings emphasize the reliability and practicality of operando EIS-DRT analysis in diagnosing the MEA electrolyzer and offer promising avenues for further improvements in the CO₂ electrolysis lifespan.

We investigate trivalent doping of tin halide perovskites as a means to decrease p-doping and control defect activity. Through density functional theory calculations and experimental characterization, we demonstrate that doping with scandium, lanthanum, and cerium successfully accomplishes Fermi level upshift, reducing background carrier concentration and defect densities, thereby improving material performance. Solar cell fabrication and testing highlight the doping efficacy, with lanthanum delivering increased photocurrent and open circuit voltage compared to control devices, despite being nonoptimized. This research underscores the potential of cation doping in enhancing the functionality of p-doped tin perovskites for advanced optoelectronic applications.

Locally concentrated electrolytes are promising candidates for highly reversible lithium–metal anodes (LMAs) but heavily rely on cosolvents containing −CF₃ and/or −CF₂– groups. The use of these hazardous per- and polyfluoroalkyl substances (PFAS) leads to environmental and occupational safety concerns. Herein, ionic liquids and anisole are employed as solvents and cosolvent, respectively, to construct PFAS-free locally concentrated electrolytes. Anisole not only promotes the ion transport of the electrolytes via inducing a nanophase-segregation solution structure but also modulates the solid electrolyte interphase by affecting the deposition of organic cations and anions on LMAs as well as the conversion of anions to LiF. Optimizing the anisole content enables Li plating/stripping Coulombic efficiency up to 99.71% from 99.19% achieved with the anisole-free ionic liquid electrolyte. As a result, Li/LiFePO₄ and Li/sulfurized-polyacrylonitrile cells employing such an electrolyte and 1.5-fold lithium metal excess achieve stable cycling for 400 and 350 cycles, respectively, with 90% capacity retention.

Disordered rocksalt oxide (DRX) cathodes are promising candidates for next-generation Co- and Ni-free Li-ion batteries. While fluorine substitution for oxygen has been explored as an avenue to enhance their performance, the amount of fluorine incorporated into the DRX structure is particularly challenging to quantify and impedes our ability to relate fluorination to electrochemical performance. Herein, an experimental–computational method combining ⁷Li and ¹⁹F solid-state nuclear magnetic resonance, and ab initio cluster expansion Monte Carlo simulations, is developed to determine the composition of DRX oxyfluorides. Using this method, the synthesis of Mn- and Ti-containing DRX via standard high temperature sintering and microwave heating is optimized. Further, the upper fluorination limit attainable using each of these two synthesis routes is established for various Mn-rich DRX compounds. A comparison of their electrochemical performance reveals that the capacity and capacity retention mostly depend on the Mn content, while fluorination plays a secondary role.

Strain is an important property in halide perovskite semiconductors used for optoelectronic applications because of its ability to influence device efficiency and stability. However, descriptions of strain in these materials are generally limited to bulk averages of bare films, which miss important property-determining heterogeneities that occur on the nanoscale and at interfaces in multilayer device stacks. Here, we present three-dimensional nanoscale strain mapping using Bragg coherent diffraction imaging of individual grains in Cs_0.1FA_0.9Pb(I_0.95Br_0.05)₃ and Cs_0.15FA_0.85SnI₃ (FA = formamidinium) halide perovskite absorbers buried in full solar cell devices. We discover large local strains and striking intragrain and grain-to-grain strain heterogeneity, identifying distinct islands of tensile and compressive strain inside grains. Additionally, we directly image dislocations with surprising regularity in Cs_0.15FA_0.85SnI₃ grains and find evidence for dislocation-induced antiphase boundary formation. Our results shine a rare light on the nanoscale strains in these materials in their technologically relevant device setting.

Metal–organic frameworks (MOFs) are promising electrochromic materials known for their rapid response speed and ability to transition through multiple colors. However, typical MOF films suffer from slow response times and poor stability due to inappropriate pore sizes, weak substrate interaction, and limited bond reversibility. This study addresses these challenges by modifying F-doped SnO₂ with 4-mercaptobenzoic acid and fabricating Ni-IRMOF-74@MBA films using 3,3′-dihydroxy-4,4′-biphenyldicarboxylic acid. The optimized film exhibits a rapid response (1.9 s/2.0 s), high efficiency (331.0 cm² C^–1), and favorable stability (95.7% retention after 4500 cycles), transitioning from transparent to green at 0.8 V and deep-brown at 1.6 V due to Li⁺ interaction with the ligand. The resulting electrochromic device shows improved response (2.3 s/7.9 s) and stability (85% retention after 1200 cycles). This work presents a significant advancement in developing MOFs for electrochromic applications.

An integration of perovskite and cadmium telluride (CdTe) solar cells in a tandem configuration has the potential to yield efficient thin-film tandem solar cells. Owing to the promise of higher efficiency at low cost, the presented study aims to explore the potential for combining this commercially established CdTe photovoltaics (PV) with next-generation perovskite PV. Here, we developed four-terminal (4-T) CdTe/perovskite tandem solar cells, starting with 18.3% efficient near-infrared-transparent perovskite solar cells (NIR-TPSCs) with an average transmission (T_avg) of 24.76% in the 300–900 nm wavelength range. These were then integrated with 19.56% efficient opaque CdTe solar cells, achieving 23.42% efficiency in a 4-T tandem configuration. Additionally, using a refractive index matching liquid increases the overall power conversion efficiency (PCE) to 24.2%. This pioneering achievement marks the first instance of a 4-T CdTe/perovskite thin-film tandem solar cell exceeding a PCE of 24.2%, a significant 123.72% increase in overall PCE.