ORCID Profile
0000-0003-0614-5537
Current Organisations
California Institute of Technology
,
University of Bayreuth
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Publisher: Wiley
Date: 02-09-2020
Publisher: Wiley
Date: 25-06-2018
Publisher: Wiley
Date: 07-07-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7TA11119C
Abstract: Hierarchical MoS 2 /C microspheres are synthesized via a facile hydrothermal method, which enable reversible and fast Na storage.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9TA11913B
Abstract: A dual-phase MoS 2 with expanded interlayer distance is fabricated for sodium storage. The dual-phase MoS 2 shows significantly improved electrical conductivity and enhanced Na + diffusivity compared to the common 2H-MoS 2 .
Publisher: Wiley
Date: 29-06-2015
Publisher: Elsevier BV
Date: 10-2022
Publisher: American Chemical Society (ACS)
Date: 06-07-2022
DOI: 10.26434/CHEMRXIV-2022-RS2M8
Abstract: Electrochemical impedance spectroscopy (EIS) is a widespread characterization technique used to study electrochemical systems. However, several shortcomings still limit the application of this technique. First, EIS data is intrinsically noisy, hindering spectra regression and prediction at unknown frequencies. Second, many physicochemical properties, such as the polarization resistance, are determined through non-unique equivalent circuits. Third, probed frequencies are usually log-spaced with a fixed number of points per decade, which is not necessarily optimal. This article illustrates how Gaussian processes (GPs) can overcome these three issues by showing that GPs can successfully filter EIS data and be used to determine the polarization resistance as a stochastic variable. Lastly, a GP-based, active-learning framework is developed to select EIS frequencies optimally for quick and accurate measurements.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8NR07106C
Abstract: Lithium–oxygen batteries (LOBs) possess the highest theoretical specific density among all types of lithium batteries, making them ideal candidates to replace the current Li ion batteries for next-generation electric vehicle applications.
Publisher: Wiley
Date: 27-12-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1TA02925H
Abstract: Atomically dispersed Co–Fe dual sites on nitrogen doped microporous carbon are constructed for ORR with superior performance, while XAS, differential PDF dPDF and DFT studies reveal the relationship between the catalytic performance and the local chemical environment.
Publisher: Elsevier BV
Date: 08-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8NR03942A
Abstract: Ternary metal sulfides and ternary metal oxides have received much attention as potential electrodes for high performance rechargeable batteries.
Publisher: Elsevier BV
Date: 04-2018
Publisher: American Chemical Society (ACS)
Date: 09-2021
Publisher: Elsevier BV
Date: 2023
Publisher: Elsevier BV
Date: 11-2015
Publisher: American Chemical Society (ACS)
Date: 11-12-2017
Publisher: American Chemical Society (ACS)
Date: 14-09-2015
Publisher: The Electrochemical Society
Date: 03-2023
Abstract: Electrochemical impedance spectroscopy (EIS) is used widely in electrochemistry. Obtaining EIS data is simple with modern electrochemical workstations. Yet, analyzing EIS spectra is still a considerable quandary. The distribution of relaxation times (DRT) has emerged as a solution to this challenge. However, DRT deconvolution underlies an ill-posed optimization problem, often solved by ridge regression, whose accuracy strongly depends on the regularization level λ . This article studies the selection of λ using several cross-validation (CV) methods and the L-curve approach. A hierarchical Bayesian DRT (hyper- λ ) deconvolution method is also analyzed, whereby λ 0 , a parameter analogous to λ , is obtained through CV. The analysis of a synthetic dataset suggests that the values of λ selected by generalized and modified generalized CV are the most accurate among those studied. Furthermore, the analysis of synthetic EIS spectra indicates that the hyper- λ approach outperforms optimal ridge regression. Due to its broad scope, this research will foster additional research on the vital topics of hyperparameter selection for DRT deconvolution. This article also provides, through pyDRTtools, an implementation, which will serve as a starting point for future research.
Publisher: Wiley
Date: 23-01-2022
DOI: 10.1002/INF2.12288
Abstract: Rechargeable sodium metal batteries (SMBs) have emerged as promising alternatives to commercial Li‐ion batteries because of the natural abundance and low cost of sodium resources. However, the overuse of metallic sodium in conventional SMBs limits their energy densities and leads to severe safety concerns. Herein, we propose a sodium‐free‐anode SMB (SFA‐SMB) configuration consisting of a sodium‐rich Na superionic conductor‐structured cathode and a bare Al/C current collector to address the above challenges. Sodiated Na 3 V 2 (PO 4 ) 3 in the form of Na 5 V 2 (PO 4 ) 3 was investigated as a cathode to provide a stable and controllable sodium source in the SFA‐SMB. It provides not only remarkable Coulombic efficiencies of Na plating/stripping cycles but also a highly reversible three‐electron redox reaction within 1.0–3.8 V versus Na/Na + confirmed by structural/electrochemical measurements. Consequently, an ultrahigh energy density of 400 Wh kg −1 was achieved for the SFA‐SMB with fast Na storage kinetics and impressive capacity retention of 93% after 130 cycles. A narrowed voltage window (3.0–3.8 V vs. Na/Na + ) further increased the lifespan to over 300 cycles with a high retained specific energy of 320 Wh kg −1 . Therefore, the proposed SFA‐SMB configuration opens a new avenue for fabricating next‐generation batteries with high energy densities and long lifetimes. image
Publisher: Wiley
Date: 22-10-2023
Publisher: Wiley
Date: 21-06-2021
Abstract: Hybrid organic–inorganic perovskites are one of the promising candidates for the next‐generation semiconductors due to their superlative optoelectronic properties. However, one of the limiting factors for potential applications is their chemical and structural instability in different environments. Herein, the stability of (FAPbI 3 ) 0.85 (MAPbBr 3 ) 0.15 perovskite solar cell is explored in different atmospheres using impedance spectroscopy. An equivalent circuit model and distribution of relaxation times (DRTs) are used to effectively analyze impedance spectra. DRT is further analyzed via machine learning workflow based on the non‐negative matrix factorization of reconstructed relaxation time spectra. This exploration provides the interplay of charge transport dynamics and recombination processes under environment stimuli and illumination. The results reveal that in the dark, oxygen atmosphere induces an increased hole concentration with less ionic character while ionic motion is dominant under ambient air. Under 1 Sun illumination, the environment‐dependent impedance responses show a more striking effect compared with dark conditions. In this case, the increased transport resistance observed under oxygen atmosphere in equivalent circuit analysis arises due to interruption of photogenerated hole carriers. The results not only shed light on elucidating transport mechanisms of perovskite solar cells in different environments but also offer an effective interpretation of impedance responses.
Publisher: American Chemical Society (ACS)
Date: 26-07-2022
DOI: 10.26434/CHEMRXIV-2022-B601X
Abstract: Electrochemical impedance spectroscopy (EIS) is a characterization technique widely used to evaluate the properties of electrochemical systems. The distribution of relaxation times (DRT) has emerged as a model-free alternative to equivalent circuits and physical models to circumvent the inherent challenges of EIS analysis. Deep neural networks (DNNs) can be used to deconvolve DRTs, but several issues remain, e.g., the long training time, the DNN accuracy, and the deconvolution of DRTs with negative peaks. The DNN-DRT model was developed here to address these fundamental limitations. Specifically, a pretraining step was included to decrease the computation time. A thorough error analysis was also conducted to evaluate the different components of the DRT and impedance errors to ultimately decrease them. Lastly, the training loss function was modified to handle DRTs with negative peaks. These different advances were validated with an array of synthetic EIS spectra and real EIS spectra from a lithium-ion battery, a solid oxide fuel cell, and a proton exchange membrane fuel cell. Moreover, this new model outperformed in most cases the previously developed DRTtools and deep-DRT model. Overall, we envision that this research will open the venue for more DNN-based analyses of EIS data for electrochemical systems.
Publisher: American Chemical Society (ACS)
Date: 25-04-2022
Publisher: Elsevier BV
Date: 12-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TA05298A
Abstract: A scalable scaffold made of carbon nanofibers modified with embedded ZnO nanoparticles as facile nucleation sites for stable plating and stripping of Na is developed, leading to much ameliorated cyclic stability at high current densities.
Publisher: Elsevier BV
Date: 10-2013
Publisher: Elsevier BV
Date: 2021
Publisher: American Chemical Society (ACS)
Date: 15-04-2015
Abstract: Mixed conducting perovskite oxides are promising catalysts for high-temperature oxygen reduction reaction. Pristine SrCoO(3-δ) is a widely used parent oxide for the development of highly active mixed conductors. Doping a small amount of redox-inactive cation into the B site (Co site) of SrCoO(3-δ) has been applied as an effective way to improve physicochemical properties and electrochemical performance. Most findings however are obtained only from experimental observations, and no universal guidelines have been proposed. In this article, combined experimental and theoretical studies are conducted to obtain fundamental understanding of the effect of B-site doping concentration with redox-inactive cation (Sc) on the properties and performance of the perovskite oxides. The phase structure, electronic conductivity, defect chemistry, oxygen reduction kinetics, oxygen ion transport, and electrochemical reactivity are experimentally characterized. In-depth analysis of doping level effect is also undertaken by first-principles calculations. Among the compositions, SrCo0.95Sc0.05O(3-δ) shows the best oxygen kinetics and corresponds to the minimum fraction of Sc for stabilization of the oxygen-vacancy-disordered structure. The results strongly support that B-site doping of SrCoO(3-δ) with a small amount of redox-inactive cation is an effective strategy toward the development of highly active mixed conducting perovskites for efficient solid oxide fuel cells and oxygen transport membranes.
Publisher: Elsevier BV
Date: 03-2014
Publisher: Springer Science and Business Media LLC
Date: 09-2022
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4TA01593B
Abstract: La slightly-doped BaFeO 3 as a SOFC cathode material is studied by experiments with single crystal thin films and molecular simulations.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Wiley
Date: 11-03-2022
Abstract: Anode‐supported protonic ceramic fuel cells (PCFCs) are highly promising and efficient energy conversion systems. However, several challenges need to be overcome before these systems are used more widely, including the poor sintering of recently developed proton‐conducting oxides and the decreased proton conductivity due to detrimental reactions between the nickel from anode and the electrolyte occurring during high‐temperature co‐sintering. Herein, a Ni doping strategy to increase the electrolyte sintering, suppress the detrimental phase reactions, and generate stable Ni nanoparticles for enhanced performance is proposed. A nickel‐doped perovskite oxide is developed with the nominal composition of Ba(Zr 0.1 Ce 0.7 Y 0.1 Yb 0.1 ) 0.95 Ni 0.05 O 3− δ . Acting as a sintering aid, such a small amount of nickel effectively improves the sintering of the electrolyte. Concomitantly, reactions between nickel and the Ni‐doped ceramic phase are suppressed, turning detrimental phase reactions into benefits. The nickel doping further promotes the formation of Ni nanoparticles, which enhance the electrocatalytic activity of the anode toward the hydrogen oxidation reaction and improve the charge transfer across the anode–electrolyte interface. As a result, highly efficient PCFCs are developed. The innovative anode developed in this work also shows favorable activity toward ammonia decomposition, making it highly promising for use in direct ammonia fuel cells.
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4RA03028A
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CC04895A
Abstract: Layered PrBaMn 2 O 5+δ catalysts, facilely prepared by annealing pristine Pr 0.5 Ba 0.5 MnO 3−δ in H 2 , exhibit remarkably enhanced oxygen reduction/evolution reaction activities.
Publisher: Wiley
Date: 13-10-2022
Abstract: Perovskite oxides are intriguing electrocatalysts for the oxygen evolution reaction, but both surface (e.g., composition) and bulk (e.g., lattice oxygen) properties should be optimized to maximize their participation in offering favorable activity and durability. In this work, it is demonstrated that through introducing exogenous Fe 3+ () into the liquid electrolyte, not only is the reconstructed surface stabilized and optimized, but the lattice oxygen diffusion is also accelerated. As a result, compared to that in Fe‐free 0.1 m KOH, PrBa 0.5 Sr 0.5 Co 2 O 5+δ in 0.1 m KOH + 0.1 m m Fe 3+ demonstrates a tenfold increment in activity, an extremely low Tafel slope of ≈50 mV dec ‐1 , and outstanding stability at 10.0 mA cm ‐2 for 10 h. The superior activity and stability are further demonstrated in Zn–air batteries by presenting high open‐circuit voltage, narrow potential gap, high power output, and long‐term cycle stability (500 cycles). Based on experimental and theoretical calculations, it is discovered that the dynamical interaction between the Co hydr(oxy)oxide from surface reconstruction and intentional Fe 3+ from the electrolyte plays an important role in the enhanced activity and durability, while the generation of a perovskite‐hydr(oxy)oxide heterostructure improves the lattice oxygen diffusion to facilitate lattice oxygen participation and enhances the stability.
Publisher: Elsevier BV
Date: 2023
Publisher: Elsevier BV
Date: 03-2015
Publisher: Wiley
Date: 04-08-2021
Abstract: Reversible protonic ceramic cells (RePCCs) can facilitate the global transition to renewable energy sources by providing high efficiency, scalable, and fuel‐flexible energy generation and storage at the grid level. However, RePCC technology is limited by the lack of durable air electrode materials with high activity toward the oxygen reduction/evolution reaction and water formation/water‐splitting reaction. Herein, a novel nanocomposites concept for developing bifunctional RePCC electrodes with exceptional performance is reported. By harnessing the unique functionalities of nanoscale particles, nanocomposites can produce electrodes that simultaneously optimize reaction activity in both fuel cell/electrolysis operations. In this work, a nanocomposite electrode composed of tetragonal and Ruddlesden–Popper (RP) perovskite phases with a surface enriched by CeO 2 and NiO nanoparticles is synthesized. Experiments and calculations identify that the RP phase promotes hydration and proton transfer, while NiO and CeO 2 nanoparticles facilitate O 2 surface exchange and O 2‐ transfer from the surface to the major perovskite. This composite also ensures fast (H + /O 2‐ /e ‐ ) triple‐conduction, thereby promoting oxygen reduction/evolution reaction activities. The as‐fabricated RePCC achieves an excellent peak power density of 531 mW cm ‐2 and an electrolysis current of −364 mA cm ‐2 at 1.3 V at 600 °C, while demonstrating exceptional reversible operation stability of 120 h at 550 °C.
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3TA13253F
Publisher: Wiley
Date: 19-12-2016
Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 10-2021
Location: United States of America
No related grants have been discovered for Francesco Ciucci.