ACS Applied Energy Materials最新文献

Integration of diverse functional materials offers a multifaceted approach to tackle the challenges of developing highly conductive, durable, and cost-effective membrane electrolytes for energy applications. A simple, low cost protic ionic liquid (PIL) “triazolium methanesulfonate” (C₂H₄N₃⁺CH₃SO₃^–) was entrapped into the pores of zirconium-based metal–organic framework (MOF), MOF 808 (Zr₆O₄(OH)₄(BTC)₂(HCOO)₅(H2O)₁(OH)₁) to develop a hybrid proton conductor (TrzIL@M). This generated a new class of material that can harness the intrinsic properties of rigid host-soft guest, resulting in synergistic interplay that forms ordered, long-range ion conducting ducts and prevents PIL leaching when incorporated in a polymer matrix. Further, electrolytes are susceptible to degradation by reactive oxygen species. To combat this, we drew inspiration from biological systems and utilized the renewable antioxidant vitamin E (α-tocopherol) as a potent radical scavenger. Finally, a mixed matrix membrane electrolyte was developed by incorporating TrzIL@M and vitamin E into a SPEEK matrix. The resulting membrane (SP/TrzIL@ME) exhibited a high conductivity of 0.035 S/cm at 100 °C ∼2.7 times upsurge in comparison to pristine SPEEK membrane, while PIL loss was reduced by 18%. SP/TrzIL@ME achieved maximum current density of 1327 mA/cm² and peak power density 245 mW/cm² in zero-humidified conditions. SP/TrzIL@ME operated effectively in nonhumidified state mitigating flooding, swelling, and dimensional distortion associated with humidity-dependent membranes. Notably, the membrane could retain 91% of open-circuit voltage after five cycles (50 h) durability testing attributed to the scavenging activity and recyclability of vitamin E, establishing the PEM as a potential candidate for proton exchange membrane fuel cells.

Sodium ion hybrid capacitors (SIHCs) are garnering substantial interest in the energy storage field due to their unique capability to integrate high energy density and power density with the economic advantages of abundant sodium resources. However, the kinetic mismatch between battery-type anodes and capacitor-type cathodes presents a significant obstacle, severely limiting the performance potential of high-performance SIHCs. Herein, we report the development of a favorable pseudocapacitive Na⁺ storage nanohybrid, featuring VC nanodots confined within an N-doped carbon nanofiber network (VC@N-CNFs), which has been successfully applied to SIHCs. The integration of VC nanodots with a conductive carbon fiber framework significantly enhances electron transport and provides ample interface between the electrolyte and VC active material, thereby effectively improving the reaction kinetics of the anode. Consequently, the VC@N-CNFs demonstrate exceptional sodium storage capability, achieving a high capacity of 160.2 mA h g^–1 at 1 A g^–1 after 2000 cycles. Thanks to the favorable kinetic matching between the anode and cathode, the assembled SIHCs exhibit high energy and power densities of 97.8 W h kg^–1 and 4118.3 W kg^–1, respectively, alongside remarkable cycling performance, retaining 73.5% of their capacity after 6000 cycles.

Li-rich Mn-rich layered oxides (LLOs) are considered key cathode candidates for next-generation lithium-ion batteries (LIBs) because of their high specific capacity that owes to the anionic redox. However, the poor cycling performance, low initial Coulombic efficiency, and unsatisfactory rate performance of LLOs hinder their practical application. Herein, a uniform multifunctional Layered@Li₄Mn₅O₁₂@PDA-Li₂SO₄ coating layer is constructed on the surface of a Li-rich material by a simple one-step process. By constructing a zero-strain Li₄Mn₅O₁₂ spinel with more Mn⁴⁺ on the particle surface, the Jahn–Teller effect and the resulting manganese dissolution can be avoided. PDA provides a chemical protective layer that can reduce the growth of an undesirable cathode electrolyte interphase and also promotes the rapid ion migration of electrons/ions. This coating layer can significantly improve the initial Coulombic efficiency (ICE), rate performances, and cycling stability of the material. The as-prepared LLO exhibits a greatly strengthened specific capacity of 270.2 mAh/g with an enhanced ICE of 83.38% and long-term cyclability of 79.14% retention after 500 cycles. The as-prepared LLO’s discharge specific capacity at 10C is 131 mAh/g, whereas the pristine LLO only has 93 mAh/g. This study elucidates the mechanism of the composite surface structure and establishes the relationship between lithium-ion interfacial conductivity and electrochemical performance, offering a strategy for near-surface design of LLOs in high-energy-density LIBs.

Solid polymer electrolytes (SPEs) confront the major challenge of low ionic conductivity. The Li⁺ local coordination environment in SPEs affects the ionic conductivity. Herein, a highly ionic conductive SPE is designed and experimentally realized via governing the Li⁺ local coordination environment through 4-acetylphenylboronic acid (APBA). The –OH functional groups in APBA react with F atoms in the PVDF-HFP polymer chain segment and O atoms in TFSI^– to form the OH···F hydrogen bond and the OH···O hydrogen bond. This weakens the Li⁺ local coordination with PVDF-HFP and TFSI^–, facilitating more free-Li⁺ release and strengthening the molecular dynamics of Li⁺. This variation results in the greatly increased Li⁺ ionic conductivity from 0.63 × 10^–4 to 2.39 × 10^–4 S/cm of SPE with APBA at 25 °C. This electrolyte makes the symmetric cells full cells with promising electrochemical performance. The strategy provided here is helpful for the development of highly ionic conductive SPEs.

The accelerated discovery and optimization of materials relies on the integration of advanced experimental techniques with data-driven methodologies. In this work, Bayesian optimization (BO) is applied to optimize the ultrasonic spray pyrolysis (USP) process for the deposition of copper oxides, targeting high-quality Ga₂O₃–Cu₂O heterojunctions for optoelectronic applications. By employing BO with an initial data set of 12 samples and conducting 4 USP parameter optimization cycles, significant improvements in device performance are achieved, with the open-circuit voltage increasing from 288 to 804 mV. During the optimization process, the performance of the model declines, necessitating the identification of a reliable subset of samples from the full data set. Through the application of BO, the cross-validation error of the model is minimized based on the sample selection, whereby accuracy is restored and generalizability is achieved. The subsequent model evaluation reveals two distinct deposition regimes, each characterized by unique process conditions, leading to specific material properties and device performances. These findings not only demonstrate the application of a data-driven experimental workflow in the context of thin film deposition but also highlight the importance of robust data validation and model evaluation.

The selective staining of cellulose materials is crucial for the accurate investigation of the binder distribution in electrodes of lithium-ion batteries. This paper investigates how (heptadecafluorodecyl)trimethoxysilane selectively reveals the binder distribution via EDS. Selectivity was granted by investigating individual electrode components: graphite, carbon black (CB), styrene–butadiene rubber (SBR), and sodium carboxymethyl cellulose (NaCMC). Each component was treated with the staining agent, stored at 60 °C for 16 h, washed with ethanol, and analyzed via energy dispersive spectroscopy (EDS). Only NaCMC shows a significant increase in fluorine concentration, proving selective staining. The study further explores the reaction mechanism by varying the degree of substitution (DS) of NaCMC, showing a correlation between carboxyl moieties and fluorine concentration and identifies 16 h of heated storage as a viable staining condition. Finally, the method’s applicability was demonstrated by comparing binder distribution in electrodes dried at different rates, revealing the NaCMC binder distribution via EDS.

Ferroelectric materials have emerged as promising candidates for piezoelectric nanogenerators, attributed to their superior energy conversion efficiency derived from inherent polarization characteristics. Polar metal–ligand assemblies represent advantageous alternatives to conventional inorganic ceramics and organic polymers, offering tunable electronic properties, environmental benignity, and enhanced energy conversion capabilities. We demonstrate an octahedral [[Co₆(H₂O)₁₂(TPTA)₈](NO₃)₁₂·50H₂O] cage assembly exhibiting pronounced ferroelectric behavior, characterized by a P–E hysteresis loop with a remnant polarization of 6.84 μC cm^–2. The ferroelectric and piezoelectric properties of 1 were unambiguously confirmed through the visualization of electrical domains in single crystals and crystalline thin films via piezoresponse force microscopy (PFM). Single-point, bias-dependent PFM spectroscopy measurements revealed characteristic amplitude-butterfly and phase-hysteresis loops, substantiating the piezoelectric nature of the material. Piezoelectric energy harvesting investigations conducted on polydimethylsiloxane (PDMS) composite materials revealed a maximum peak output voltage of 12.20 V and a power density of 14.85 μW cm^–2 for the optimized 20 wt % 1-PDMS composite device. The practical utility was validated through the implementation of a smart pressure sensor, wherein a mat device, constructed from five parallel-connected independent devices, successfully functioned as a sensor capable of illuminating a commercial LED under gentle mechanical stimulation. These findings establish the potential of this cage system for integration into self-powered sensor technologies.

The efficiency and stability of perovskite photovoltaic devices (PPVDs) are heavily influenced by defects and external dopants within the perovskite layer and by external environmental factors, such as oxygen, moisture, light, and heat. Still, the impact of dopant diffusion from the hole transport layer toward the perovskite absorbing layer as a function of the temperature is not fully understood. This study investigates the diffusion effect of lithium (Li) ions from Spiro-OMeTAD into the double-cation perovskite layer for PPVDs with regular architecture. For Li-containing devices, temperature-dependent capacitance–voltage (C–V) measurements and Mott–Schottky analysis, within the temperature range of 280–353 K, reveal an increased space charge density. This suggests a higher ionic mobility with increasing temperature. Consequently, a decrease in the depletion region width was observed as the temperature increased. Additionally, C–V profiles reveal two distinct peaks, M₁ and M₂, correlated with two different regions within the perovskite layer: the first peak is related with the embedded perovskite within the mesoporous TiO₂ scaffold, and, the second one with the perovskite capping layer. On another side, in aged Li-containing devices, the M₂ peak shifts to lower voltages (from 1.07 to 0.95 V) with aging indicating changes in its electronic structure and charge distribution in the embedded perovskite due to Li-ion diffusion. This accumulation of Li ions correlates with reduced device stability, highlighting that Li-ion migration adversely impacts long-term performance. The results emphasize differences in charge carrier distribution and interactions within the device, leading to variations in the local electronic properties. Stability tests revealed that after 280 days, Li-free devices retained approximately 75% of their initial efficiency, while Li devices maintained only 35%. These findings emphasize the role of Li in influencing degradation mechanisms and the importance of managing dopant migration for long-term device stability.

Introducing defects is one of the promising approaches for enhancing the thermoelectric property. In this study, we substantially reduce thermal conductivity while maintaining a high thermoelectric power factor (PF) by selectively manipulating O^2– anion in domain-engineered SnO₂ with conduction and valence bands mainly composed of Sn 5s and O 2p orbitals, respectively. Ion implantation can generate O defects more easily than Sn defects, resulting in a small impact on the Sn 5s conduction band and the formation of the O defect resonant level. The lattice thermal conductivity of the arsenic-implanted epitaxial SnO₂ films with the manipulated O^2– anions (2.6 Wm^–1 K^–1) is approximately half that of Sb-doped films without them (4.7 Wm^–1 K^–1), while the maximum PF of arsenic-implanted epitaxial SnO₂ films remains relatively high owing to the high Seebeck coefficient originating from an effective mass increase. This selective O^2– anion manipulation is an outstanding methodology of selectively causing thermal conductivity reduction while maintaining a high PF.