Advanced Energy and Sustainability Research最新文献

Structural batteries that unite mechanical integrity with electrochemical function hinge on carbon fiber anodes capable of sustaining efficient lithium transport. Carbon fibers possess unique microstructures and multifunctional demands, yet their lithium transport kinetics remain largely unexplored in the context of structural batteries. Here, diffusion processes and interfacial characteristics are quantified in two intermediate-modulus polyacrylonitrile-based fibers (T800S and T800H), which share identical core microstructures but differ in polymer sizing and electrode architecture. T800S outperforms T800H in liquid electrolyte, delivering higher lithiation capacity (≈295 vs. ≈283 mAh g⁻¹) and lower irreversible loss (31% vs. 36%), consistent with more efficient solid electrolyte interphase (SEI) formation and faster charge-transfer dynamics. Under structural battery electrolyte conditions, both fiber types exhibit suppressed capacity, with diffusion coefficients reduced by up to two orders of magnitude (≈10–13 to ≈10–15 cm² s⁻¹), as revealed by galvanostatic intermittent titration and impedance spectroscopy. Elevated charge-transfer resistance and diminished interfacial capacitance further highlight the transport limitations imposed by the biphasic structural electrolyte matrix. The results demonstrate that fiber microstructure governs performance in liquid electrolytes, whereas interfacial chemistry and electrode architecture dominate under structural battery electrolyte operation. This mechanistic framework identifies interface engineering and mesoscale design as key strategies for advancing multifunctional structural energy storage.

Lithium Metal Batteries

Post- mortem analysis of an end-of-life Li metal battery reveals that electrolyte amount is still present (no “dry-out”), even at lean electrolyte conditions. Rather, the Li metal itself suffers from the latter. More details can be found in the Research Article by Isidora Cekic-Laskovic, Johannes Kasnatscheew, and co-workers (DOI: 10.1002/aesr.202500233).

Interplay of magnetic susceptibility and vapor phase nucleation in magnetic field-assisted chemical vapor deposition (mf-CVD) enables precise control over phase evolution, crystallographic orientation, and surface texturing in metal oxide thin films. The synthesis of hematite (α-Fe₂O₃) thin films via chemical vapor deposition using [Fe₂(O^tBu)₆] as a molecular precursor is reported. Applying an external magnetic field (1 T) during deposition significantly alters the microstructure of the hematite films, reflected in superior photoelectrochemical (PEC) performance. Relative to zero-field deposition, mf-CVD increased the photocurrent density of hematite by 74%, attributed to magnetically induced texturing and densification, both enhancing charge separation and transfer efficiencies. Magnetic field-assisted hematite growth also increases the electrochemically active surface area, while a 33 mV photovoltage gain suggests a stronger built-in electric field in the α-Fe₂O₃-1 T film. Electrochemical impedance spectroscopy further confirms a reduced surface state density supporting improved interfacial charge dynamics. Furthermore, the magnetically altered material exhibits remarkable stability for 100 h of PEC operation. The results highlight hematite as a model photoanode for elucidating how magnetic fields modulate active domains in metal oxides, offering an innovative process to transform materials through applied fields.

Lithium Ion Batteries

Incorporating lithium directly on the anode is a possible prelithiation strategy to compensate capacity losses in a lithium ion battery. Physical vapor deposition (PVD) is regarded as beneficial due to a homogenous lithium distribution. However, it is only valid for low degree of prelithiation (DOP) while high DOPs limit the PVD technique, as even Li agglomerates can emerge. More details can be found in the Research Article by Johannes Kasnatscheew and co-workers (DOI: 10.1002/aesr.202500150)

Li plating significantly contributes to the ageing of lithium-ion batteries (LIBs). An in-depth understanding of Li-ion intercalation kinetics into graphite, still being widely used as anode material, and the subsequent phase formation of Li_xC₆ compounds, is necessary to understand kinetic limits and prevent Li plating. Diffraction and colorimetric studies have explored these processes, noting graphite color changes during (de)intercalation. However, these methods fall short of examining graphite intercalation at a microscopic scale, essential for understanding intercalation kinetics and Li plating onset conditions. This study employs a high-resolution light microscope under inert gas to examine lithiation processes in graphite anodes at the particle level across various C-rates. Qualitative descriptions and quantitative assessments are achieved through colorimetric analysis based on hue and saturation, complemented by machine learning-based segmentation. The results show an increased spatial heterogeneity of lithiation stages both between particles and within individual particles, with increasing C-rate. Notably, up to three stages coexist in one particle, and LiC₆ is present at 50% (SOC) state of charge even when lithiated with 0.2C. At 1C charging, 4% and 32.5% of the surface is covered with Li deposits at 30% and 50% SOC, respectively, with underlying graphite particles showing LiC₆.

Mild pulsed laser postprocessing of catalyst dispersions via pulsed laser defect engineering in liquids has emerged as an effective tool to enhance catalytic activity. This approach enables the introduction of cations or point defects and the modification of surface properties with single-pulse precision in flow-through reactors, while requiring only low laser energies. To date, it has been applied primarily to oxides, but not to metallic or alloyed catalysts. Here, we investigate the impact of nanosecond-pulsed ultraviolet (ns-UV) laser irradiation on Pd₃₀Ru₃₀Pt₁₀Ir₁₀Rh₂₀ high-entropy alloy (HEA) nanoparticles, a theoretically proposed composition for highly active electrocatalytic oxygen reduction reaction (ORR). After UV laser processing, the HEA nanoparticles exhibit an 80 mV lower overpotential for the acidic oxygen evolution reaction (OER) and a tenfold increase in acidic ORR activity compared to the untreated sample. These enhancements correlate with a laser-induced increase in surface charge density, while particle size and composition remain unchanged. Control experiments with iridium nanoparticles confirm an enrichment of negatively charged surface groups as the underlying factor. Remarkably, substantial performance gains are achieved at very low laser fluences of 1 mJ cm⁻² in water. Optical modeling rationalizes this unusually high efficiency, highlighting the scalability of this method for kg-scale catalyst activation, with direct relevance to green hydrogen production (OER) and fuel cell applications (ORR).

The electrochemical reduction of carbon dioxide offers a promising approach to reduce CO₂ emissions while producing valuable chemicals. To date, CO production in membrane electrode assembly (MEA) electrolyzers employing anion exchange membranes results as the most industrially viable setup. However, industrial applicability of this technology is limited by the salt precipitation problem that compromises long-term operation. In this study, we first systematically optimized key electrode components using a 5 cm² commercial cell and then validated the results in 25 and 100 cm² electrolyzer under ambient conditions. Among the investigated parameters, the polymeric binder emerges as a critical element influencing both selectivity and stability, due to its impact on salt accumulation. In the 100 cm² electrolyzer, long-term electrochemical measurements conducted at industrially relevant current density (300 mA cm⁻²) demonstrate significantly greater stability with PiperION−based cathodes, which maintained faradaic efficiency toward CO larger than 80% for 40 h operations, while Sustainion-based electrodes show a 60% drop after just 20 h. Cross-sectional elemental mapping confirms a direct correlation between the ionomeric binder and Cs salt accumulation in the electrode. This work provides valuable insight into mitigating salt formation and enhancing electrode longevity in large-scale MEA electrolyzers by efficiently tailoring the ionomeric binder.

Over the past two decades, nanoscale structures such as nanowires (NWs) based on III-V semiconductors have emerged as versatile device components in electronic and photonic applications. In particular, for photoelectrochemical applications, the high surface-to-volume ratio of NWs is expected to significantly enhance surface reaction kinetics, mainly by providing more active sites conducive to light-driven processes. However, few studies have investigated these advantages for III-V NWs. A particular challenge lies in the stability of such structures compared to more easily fabricated planar surfaces. In order to investigate the beneficial effects of GaAs-based NW structures for solar water splitting on current density, electrode stability in electrolyte, and bubble detachment, linear sweep voltammetry and scanning electron microscopy are performed before and after 2 h of operation using chronoamperometric measurements. The results show that NW absorber structures exhibit a significantly lower onset potential compared to bare substrates. The durability of NWs appears to be strongly influenced by NW geometry and defect density, both of which increase susceptibility to corrosion. Nitrogen-based passivation layers have been observed to significantly increase the longevity of NWs. These results provide valuable insights into the durability of NW-based devices, with particular relevance for their application in solar energy conversion technologies.

A rapid solid-state flash heat and quench (FHQ) synthesis approach has been used to facilitate the rapid formation of layered NCA Li-ion cathodes with low structural defects. LiNi_xCo_yAl_zO₂ (NCA) materials prepared by FHQ reveal impressive gravimetric capacity at C/10 and 10C discharge rates (195 and 150 mAh g⁻¹, respectively) after a few minutes of heating a co-precipitate mixture with LiOH, providing >95% reduction in energy needed for heat-treatment versus conventional solid state synthesis routes. Combined X-ray diffraction, neutron scattering with pair-distribution-function analysis, and X-ray absorption spectroscopy for a range of heat-treated samples are used to identify the point at which Ni²⁺−Li⁺ antisite defects are minimized in these materials, which is critical to their electrochemical performance.

In lithium metal batteries, the cycle life relevantly declines with decreasing electrolyte amount. The capacity decay is kinetically reasoned as shown by rises in cell resistances, in particular for the discharge processes, as indicated by the full capacity recovery during a constant voltage step after discharge at the end of life (EOL). Interestingly, adding fresh electrolyte after EOL only partially recovers the capacity, suggesting a different and more crucial failure origin than the assumed loss of charge carriers due to the electrolyte “dry-out”. Contrary to the cathode, the anode has higher resistances and a thicker surface layer post mortem, which is also observed in Li‖Li cells. In addition, the resistance portion of the electrolyte itself remains comparatively low during cycling, suggesting that resistance rise is dominated by the Li anode and is confirmed by exchange with fresh Li, where the capacities are recovered toward initial values, again. Based on the observations, a mechanism with a faster dry-out of Li metal pores is proposed, which decreases the electrolyte-accessible Li metal surface area, enhances local current densities, and facilitates high surface area and dead lithium. This continuously clogs and blocks the surface, reducing the practical accessible Li and eventually causing the rollover fade.