eScience最新文献

Sodium-ion batteries (SIBs) with low cost and high safety are considered as an electrochemical energy storage technology suitable for large-scale energy storage. Hard carbon, which is inexpensive and has both high capacity and low sodium storage potential, is regarded as the most promising anode for commercial SIBs. However, the commercialization of hard carbon still faces technical issues of low initial Coulombic efficiency, poor rate performance, and insufficient cycling stability, due to the intrinsically irregular microstructure of hard carbon. To address these challenges, the rational design of the hard carbon microstructure is crucial for achieving high-performance SIBs, via gaining an in-depth understanding of its structure–performance correlations. In this context, our review firstly describes the sodium storage mechanism from the perspective of the hard carbon microstructure's formation. We then summarize the state-of-art development of hard carbon, providing a critical overview of emergence of hard carbon in terms of precursor selection, microstructure design, and electrolyte regulation to optimize strategies for addressing practical problems. Finally, we highlight directions for the future development of hard carbon to achieve the commercialization of high-performance SIBs. We believe this review will serve as basic guidance for the rational design of hard carbon and stimulate more exciting research into other types of energy storage devices.

Although single-atom catalysts (SACs) have attracted enormous attention for their applications in the electrochemical reduction of CO₂ (CO₂RR) due to their extraordinary catalytic activity and well-defined active centers, neighboring effects and their influence on the electrochemical performance of SACs have not been well investigated. In this review, we present a summary of the neighboring effects on SACs for the CO₂RR process, where the surrounding atoms not only induce electronic modulation of the metal atom but also participate in the CO₂RR. Both theoretical and experimental studies have pointed out that the neighboring sites of the anchored metal center can provide second active/adsorption locations during the catalytic process, enhancing CO₂RR performance tremendously. This review supplies advanced insights into the significant roles and impacts of neighboring effects on the catalytic process, which also benefit the development of advanced SACs to achieve efficient electrocatalysis.

The anionic redox reaction (ARR) is a promising charge contributor to improve the reversible capacity of layered-oxide cathodes for Na-ion batteries; however, some practical bottlenecks still need to be eliminated, including a low capacity retention, large voltage hysteresis, and low rate capability. Herein, we proposed a high-Na content honeycomb-ordered cathode, P2–Na_5/6[Li_1/6Cu_1/6Mn_2/3]O₂ (P2-NLCMO), with combined cationic/anionic redox. Neutron powder diffraction and X-ray diffraction of P2-NLCMO suggested P2-type stacking with rarely found P6₃22 symmetry. In addition, advanced spectroscopy techniques and density functional theory calculations confirmed the synergistic stabilizing relationship between the Li/Cu dual honeycomb centers, achieving fully active Cu³⁺/Cu²⁺ redox and stabilized ARR with interactively suppressed local distortion. With a meticulously regulated charge/discharge protocol, both the cycling and rate capability of P2-NLCMO were significantly improved, demonstrating reasonable capacity and eliminating voltage hysteresis. Overall, this work contributes a well-defined layered oxide cathode with combined cationic/anionic redox towards rational designing advanced Na-ion batteries.

Delicately designed metal–organic framework (MOF)-derived nanostructured electrocatalysts are essential for improving the reaction kinetics of the oxygen evolution reaction and tuning the selectivity of small organic molecule oxidation reactions. Herein, novel oxalate-modified hollow CoFe-based layered double hydroxide nanocages (h-CoFe-LDH NCs) and yolk–shell ZIF@CoFe-LDH nanocages (ys-ZIF@CoFe-LDH NCs) are developed through an etching–doping reconstruction strategy from a Co-based MOF precursor (ZIF-67). The distinctive nanostructures, along with the incorporation of the secondary metal element and intercalated oxalate groups, enable h-CoFe-LDH NCs and ys-ZIF@CoFe-LDH NCs to expose more active sites with high intrinsic activity. The resultant h-CoFe-LDH NCs exhibit outstanding OER activity with an overpotential of only 278 ​mV to deliver a current density of 50 ​mA ​cm⁻². Additionally, controlling the reconstruction degree enables the formation of ys-ZIF@CoFe-LDH NCs with a yolk–shell nanocage nanostructure, which show outstanding electrocatalytic performance for the selective ethylene glycol oxidation reaction (EGOR) toward formate, with a Faradaic efficiency of up to 91%. Consequently, a hybrid water electrolysis system integrating the EGOR and the hydrogen evolution reaction using Pt/C||ys-ZIF@CoFe-LDH NCs is explored for energy-saving hydrogen production, requiring a cell voltage 127 ​mV lower than water electrolysis to achieve a current density of 50 ​mA ​cm⁻². This work demonstrates a feasible way to design advanced MOF-derived electrocatalysts toward enhanced electrocatalytic reactions.

Ionic thermoelectric (i-TE) technologies can power Internet of Things (IoT) sensors by harvesting thermal energy from the environment because of their large thermopowers. Present research focuses mostly on using the interactions between ions and matrices to enhance i-TE performance, but i-TE materials can benefit from utilizing different methods to control ion transport. Here, we introduced a new strategy that employs an ion entanglement effect. A giant thermopower of 28 ​mV ​K⁻¹ was obtained in a quasi-solid-state i-TE Gelatin-CF₃SO₃K–CH₃SO₃K gel via entanglement between ${{{CF}_{3}SO}_3}^{-}$ and ${{{CH}_{3}SO}_3}^{-}$ anions. The anionic entanglement effect involves complex interactions between these two anions, slowing anionic thermodiffusion and thus suppressing bipolar effects and boosting p-type thermopower. A Au@Cu | Gelatin-CF₃SO₃K–CH₃SO₃K | Au@Cu i-TE device with a generator mode delivers a specific output energy density of 67.2 ​mJ ​m⁻² K⁻² during 2 ​h of discharging. Long-term operation of the i-TE generator for 10 days shows that the harvested energy density offers an average of 2 ​J ​m⁻² per day in a cyclic working-reactivation model at a temperature difference of 6 ​K. The results demonstrate that anionic entanglement is an effective strategy for achieving giant thermopower with i-TE gels, so they have excellent potential for powering IoT sensors.

The efficient utilization of carbon dioxide (CO₂) as a resource, comprises three key processes: CO₂ capture, catalytic conversion and product purification. Using the renewable electricity to drive these processes provides a promising pathway for mitigating the ever-increasing atmospheric CO₂ concentration whilst simultaneously addressing the growing energy demand. Although each of the three individual processes has been extensively investigated during the past decade, the rapid and economically viable reduction of CO₂ emissions still calls for the development of an integrated electrochemical system driven by the renewable electricity to achieve carbon neutrality. Herein, we report a systematic protocol to bridge the three individual CO₂ utilization processes into one coupled electrochemical system: a bipolar membrane electrodialysis (BPMED) cell generating alkaline and acidic solutions for the capture and recovery of CO₂, a flow cell with an Ag gas diffusion electrode (GDE) for the selective electrocatalytic reduction of the recovered CO₂, and an alkaline solution container for the purification of the gaseous products and recycle of the unreacted CO₂. Consequently, the coupled electrochemical system successfully captured CO₂ from the simulated flue gas and converted it into a pure syngas stream.

Electrocatalytic hydrogenation (ECH) of organics using water as hydrogen donors has been regarded as a green organic reduction technique to replace traditional chemical reactions that use sacrificial chemicals. The development of ECH process provides potential applications in the production of value-added chemicals owing to its low energy consumption, low pollution, high safety, and superior sustainability. However, its application is limited by the low conversion rate and poor selectivity toward desired products. The efficiency of ECH can be improved by rational design of electrocatalysts. This review covers several representative electrocatalytic systems (aldehydes, ketones, phenolic organics, alkynes, and organonitrogen compounds) and summarizes different ECH mechanisms, followed by thorough discussion on the modification strategies of electrocatalysts that are currently adopted to enhance the catalytic performance. Finally, in view of the current challenges for ECH, we discuss possible future directions in the field, aiming to provide guidance to the catalyst design toward highly efficient ECH reactions over different organic feedstocks.

The active layer of organic solar cells (OSCs) is composed of a p-type conjugated polymer as the donor and an n-type organic semiconductor as the acceptor. Since the report of bulk-heterojunction OSCs with soluble C₆₀ derivative PCBM as the acceptor in 1995, fullerene derivatives, including PCBM and the C₇₀ derivative PC₇₁BM, have been the dominant acceptors in OSCs for 20 years. In 2015, the A–D–A structured small molecule acceptor (SMA) was developed, which possesses the advantages of a narrow bandgap, strong absorption in the long wavelength region, and suitable electronic energy levels, in contrast to the fullerene derivative acceptors. A–D–A SMAs boost the power conversion efficiency (PCE) of OSCs to the 10–14% level. Recently, benefiting from the innovation of A–DA′D–A structured SMAs, the PCE of OSCs has rapidly increased from 15% to 19%. In this review, the development history of n-type organic semiconductor acceptor materials is briefly introduced. The molecular structures and the physicochemical and photovoltaic properties of acceptors, including fullerene derivatives and narrow bandgap SMAs, are described. In particular, the effect of regulating the molecular packing and miscibility of SMAs on their photovoltaic performance is discussed. Finally, current challenges and prospects for n-type organic semiconductor acceptors are analyzed and discussed.

Sodium-ion batteries (SIBs) have stepped into the spotlight as a promising alternative to lithium-ion batteries for large-scale energy storage systems. However, SIB electrode materials, in general, have inferior performance than their lithium counterparts because Na⁺ is larger and heavier than Li⁺. Heterostructure engineering is a promising strategy to overcome this intrinsic limitation and achieve practical SIBs. We provide a brief review of recent progress in heterostructure engineering of electrode materials and research on how the phase interface influences Na⁺ storage and transport properties. Efficient strategies for the design and fabrication of heterostructures (in situ methods) are discussed, with a focus on the heterostructure formation mechanism. The heterostructure's influence on Na⁺ storage and transport properties arises primarily from local distortions of the structure and chemomechanical coupling at the phase interface, which may accelerate ion/electron diffusion, create additional active sites, and bolster structural stability. Finally, we offer our perspectives on the existing challenges, knowledge gaps, and opportunities for the advancement of heterostructure engineering as a means to develop practical, high-performance sodium-ion batteries.

The practical applications of lithium metal batteries are limited by uncontrolled dendrite growth during cycling. Herein, we propose a simple and scalable approach to stabilize lithium metal anodes using laser scribing technology to integratively design and construct a laser-induced graphene (LIG) with lithiophilic metal oxide nanoparticles. The porous LIG and lithiophilic MnO_x nanoparticles effectively reduce the nucleation overpotential of Li and regulate uniform Li plating, while the array structure offers continuous and ultra-fast ion/electron transport channels, accelerating Li⁺ transport kinetics at high rate and high capacity. Consequently, the Li@MnO_x@LIG-a anode exhibits superior rate capability of up to 40 ​mA ​cm⁻² with low nucleation overpotential. It also can withstand ultra-high Li capacity to 20 mAh cm⁻² without dendrite growth and stably cycle for 3000 ​h with 100% depth of discharge at 40 ​mA ​cm⁻². More importantly, this technology can be expanded to other metal oxides for various metal batteries.