Nano Energy最新文献

Electrocatalytic CO₂ reduction reaction (CO₂RR) to produce multi-carbon products (C₂₊) is one of the most sustainable manners to achieve net-zero carbon emissions. Among many approaches, enriching grain boundaries (GBs) in copper (Cu) catalysts has been demonstrated to enable enhancement for C₂₊ production. However, it still lacks effective strategies to controllably synthesize abundant GBs, rendering efficient C₂₊ production a persistent challenge, especially at ampere-level current density. Herein, we propose a novel strategy, which can achieve unconventional grain fragmentation during thermal annealing and thus create controllable GB densities. The catalyst with the utmost GB density exhibits a peak C₂₊ faradaic efficiency of ca. 70.0 % in H-type cell and 68.2 % in flow cell; even more impressively, it delivers an ultra-high C₂₊ current density of 0.768 A cm⁻², outperforming most recently reported results. A combination of in situ spectroscopies and theoretical calculations reveal that the enrichment of GBs yields more active sites for a higher *CO coverage, leading to promotion of the *CO-*CO coupling process and ultimately high C₂₊ production performance.

The floating-gate organic electrochemical transistor (OECT) employs a distinct signal acquisition and amplification structure. This design offers two primary advantages: firstly, it mitigates the effects of non-specific physical adsorption during the sensing process and prevents contamination of the electrolyte solution by side reaction products, thereby enhancing detection accuracy. Secondly, it allows for an increased gate/electrolyte capacitance, optimizing the OECT’s signal amplification capability. Until now, optimizing the sensing electrode and control gate remains ambiguous. This current research uses a photosensitive liquid-solid heterojunction as the control gate. This choice is based on the observation that the photovoltage of −0.43 V remains unaffected by variations in electrode area, and any reduction in photocurrent due to area reduction can be offset by an increase in light intensity. Furthermore, given that the capacitance value of liquid-solid heterojunctions (4.386×10⁻² F) significantly surpasses other components in equivalent circuits during light radiation, these heterojunctions can be considered self-driving and quasi-non-polarized. We confirmed the viability of this structural configuration through cortisol molecule detection. The potential application of this photosensitive liquid-solid heterojunction lies in constructing high-density and high-stability biosensors, a necessity in practical applications.

The current wearable devices are largely rigid and bulky, which calls for the development of next-generation soft biocompatible technologies. Another limitation is that conventional wearable devices are generally powered by thick and non-compliant batteries, hindering the miniaturization and improvement of wearable electronics. Hydrogels have attracted tremendous attention in the field of wearable bioelectronics due to their tissue-like properties, which can minimize the mechanical mismatch between flexible devices and biological tissues. Moreover, to take advantage of physical and chemical energy from the human body or ambient environment, such as mechanical energy of human motions, body heat energy, biofuel, water or wind power from nature, more and more novel technology for portable power supply has been carried out, facilitating the improvement of wearable bioelectronics. In this review, recent advances in self-powered wearable bioelectronics based on hydrogels are summarized. Firstly, the excellent properties of hydrogels are introduced, including the prominent mechanical properties, self-healing nature, high conductivity due to the incorporation of conductive polymers or additives, interfacial adhesion functionality, biocompatibility, and antibacterial properties. Then, several novel strategies of energy harvesting are discussed, such as triboelectric nanogenerators (TENGs), piezoelectric nanogenerators (PENGs), thermoelectric nanogenerators (TEGs), biofuel cells (BFCs), hydrovoltaics, antennas, and hydrogel-based batteries. Next, some representative applications of self-powered bioelectronics are illustrated (i.e., human motion monitoring, healthcare monitoring and therapies, neural stimulation and human-machine interaction). Finally, a brief summary and outlook for self-powered hydrogel bioelectronics is presented.

Bimetallic compound-based electrodes are composed of two different metallic elements with high electrical conductivity, electrochemical activity, and considerable theoretical capacity for supercapacitors. However, conventionally grown nickel-cobalt-based compounds tend to aggregate, greatly reducing the material surface's charge diffusion channels. Hence, by a series of processes to optimize the morphology and crystal structure, the porous nest-like Ni_0.75Co_0.25(CO₃)_0.125(OH)₂·0.38 H₂O (NCCO-2) derived from cobalt metal-organic frameworks (Co-MOF) are successfully anchored on activated carbon cloth (ACC). The unique microstructure with high specific surface area and abundant microstructure enables the NCCO@ACC-2 self-supported positive electrode with enhanced kinetics and optimized charge storage behavior, thus presenting an extraordinary capacitance of 7.18 F cm⁻² and superior electrochemical stability. To assemble an asymmetric supercapacitor (ASC), nitrogen-doped ACC (NAC) is prepared as the negative electrode. Its rough surface has a large number of oxidized functional groups, graphite microstructure and defect sites for charge transfer and ion adsorption, thereby also achieving a capacitance of 8.18 F cm⁻². The NCCO@ACC-2//NAC ASC exhibits outstanding energy density (1.09 mWh cm⁻²), power density (17 mW cm⁻²) and cycle stability and rate performance. This study provides a new method for preparing high-specific-capacity nickel-cobalt-based composite materials through nanoscale structure control, and the stable and efficient strategy has broad application prospects.

Performance of electrocatalyst in an aqueous electrolyte is greatly influenced by the structure of electrolyte-electrocatalyst interface. Regulating mass transfer is important in controlling surface reactions to alter the overall reaction kinetics. Thus, modification of interfacial structures is an effective approach to improving the electrocatalytic performance. In this paper, we report the use of functionalized amine-based covalent organic frameworks (COFs) as the modifier of electrocatalytic properties by facilitating the proton transfer of hydrogen evolution reaction (HER) in an acidic medium. Results from the electrochemical solid-liquid interface (ESLI)-based density functional theory (DFT) calculations suggest that functionalized COFs increase the local hydrogen concentration at the COF-electrocatalyst interface. Our simulation data indicates the enhancement in HER activity is achieved partially through the protonation site of the secondary amine of the COF on electrode surface, suggesting a new mode of controlling interfacial proton transfer for improving the HER kinetics.

The bacterial-infected diabetic wound poses a heavy burden on the patient and society. The current electrical antibiotic administration avoids drug resistance associated with antibiotics, but their development is restricted by the complex wound microenvironments. Here we propose a new therapeutic Zn battery by rationally tailoring the electrochemistry for the wound microenvironment modulation. Poly(3,4-ethylenedioxythiophene) (PEDOT) polyelectrolyte hydrogel epidermal cathode demonstrates high adhesion strength and low interfacial impedance, enabling efficient delivery of endogenous bioelectronic cues to the wound. This wearable Zn battery combines capabilities of prolonged tissue regeneration and biofilm deconstruction while retaining 52 % discharge capacity after ten times oxygen charging. The electrochemical products and discharging microcurrent are effective in bacterial sterilization and biofilm deconstruction without impairing fibroblast growth via the synergic effects of polyelectrolyte biointerface, oxidative stress in the bacterial cell, and depletion of glutathione in the microenvironment. This battery-induced electrochemical stimulation demonstrates accelerated diabetic wound healing by guiding fibroblast migration, managing inflammation, and eliminating wound infections. This work provides a unique modality to modulate the biofilm environment through electrochemistry design for bacterial-infected chronic wound healing.

The lifetime issues caused by catalyst degradation is one of the most critical challenges for the commercial application of proton exchange membrane fuel cells. However, the understanding concerning the interactions among transport, reaction, and catalyst degradation is inadequate for further durability enhancement. Herein, a scale-bridging model that couples a cell-scaled model to reveal the reactive transport process and a catalyst-scaled model to unveil Pt degradation is proposed to capture the degradation characteristics. It is found that the heterogeneous aging is observed in both the through-plane and channel-rib directions due to the enhanced mass loss near the membrane and the water accumulation under the rib, resulting in the mitigation of the core reaction region away from the membrane, thereby causing an increase in ohmic loss after cycles. More importantly, the local oxygen transport resistance increases with degradation, leading to a remarkable cell performance loss under high current density. Additionally, the influences of cell voltage load and inlet humidity on Pt degradation are also investigated. And the proposed gradient catalyst layer shows a significant mitigating effect on Pt degradation. This work reveals the degradation-performance interactions, which is conducive to design the high-performance fuel cell to prolong lifetime.

Ionic thermoregulated osmotic energy conversion in nanochannels synergistically utilizes osmotic and thermal energy for power generation based on ionic selective transport in charged nano-membranes under salinity gradients and thermal regulations. Currently, no explicit general dimensionless formulas exist that reflect the relationship between impact factors and performance to guide performance designs. In this study, data-driven insight is presented to establish a framework for obtaining explicit and general relational expressions based on data augmentation using the similarity principle and deep learning. The original database is derived from a finite element simulation with 10,000 dimensional samples, then augmented to 30,000 dimensional samples via similarity principle-based data augmentation. Subsequently, a deep neural network model with decay algorithms is employed to expand the database to new 300,000 dimensional samples with a prediction accuracy exceeding 98 %, which are further converted to dimensionless forms for multiple linear regression. Three dimensionless and explicit formulas for the electrical potential, output power, and energy conversion efficiency are obtained, which indicate determination coefficients of 0.91, 0.93, and 0.92, respectively. Furthermore, considering actual experimental and application situations, the modified dimensionless formula of the output power predicts the experimental results with an average error of 7.80 %. This study efficiently alleviates experimental burden and facilitates engineering applications.

Interfacial polymerization (IP) is a promising approach for preparing covalent organic framework (COF) membranes in energy storage and conversion applications. However, it is a great challenge for traditional IP with water-organic phase to obtain pre-designable and robust COF membranes. Herein, a "one-pot" organic-organic IP/in situ integration approach, constructing three typical β-ketoenamine COF composite membranes with a maximum area of > 600 cm², are reported. The dual organic phases exhibit comprehensive solubility to precursors, facilitating the synthesis of more types of COFs. In this "one-pot" approach, the porous supporting substrate is in situ formed underneath the COF layer via variable-temperature evaporation of two organic solutions without transfer process. It makes some substrate polymers embedded into the COF layer and accomplishes the interlock of two layers at the interface, producing a robust composite membrane. The prepared COF composite membrane exhibits effective sieving capability for Na⁺/Mg²⁺ and achieves a maximum power density of over 1 W m⁻² in the reverse electrodialysis power generation, even using the Na⁺/Mg²⁺ mixed solution. This approach allows for preferably customization of membrane structures, which can expand the applications of COF membranes in separation.