能源化学最新文献

Sluggish storage kinetics is considered as the main bottleneck of cathode materials for fast-charging aqueous zinc-ion batteries (AZIBs). In this report, we propose a novel in-situ self-etching strategy to unlock the Palm tree-like vanadium oxide/carbon nanofiber membrane (P-VO/C) as a robust free-standing electrode. Comprehensive investigations including the finite element simulation, in-situ X-ray diffraction, and in-situ electrochemical impedance spectroscopy disclosed it an electrochemically induced phase transformation mechanism from VO to layered Zn_xV₂O₅⋅nH₂O, as well as superior storage kinetics with ultrahigh pseudocapacitive contribution. As demonstrated, such electrode can remain a specific capacity of 285 mA h g⁻¹ after 100 cycles at 1 A g⁻¹, 144.4 mA h g⁻¹ after 1500 cycles at 30 A g⁻¹, and even 97 mA h g⁻¹ after 3000 cycles at 60 A g⁻¹, respectively. Unexpectedly, an impressive power density of 78.9 kW kg⁻¹ at the super-high current density of 100 A g⁻¹ also can be achieved. Such design concept of in-situ self-etching free-standing electrode can provide a brand-new insight into extending the pseudocapacitive storage limit, so as to promote the development of high-power energy storage devices including but not limited to AZIBs.

The practical application of lithium-sulfur (Li-S) batteries, as promising next-generation batteries, is hindered by their shuttle effect and the slow redox kinetics. Herein, a tungsten and molybdenum nitride heterostructure functionalized with hollow metal-organic framework-derived carbon (W₂N/Mo₂N) was proposed as the sulfur host. The hollow spherical structure provides storage space for sulfur, enhances electrical conductivity, and inhibits volume expansion. The metal atoms in the nitrides bonded with lithium polysulfides (LiPSs) through Lewis covalent bonds, enhancing the high catalytic activity of the nitrides and effectively reducing the energy barrier of LiPSs redox conversion. Moreover, the high intrinsic conductivity of nitrides and the ability of the heterostructure interface to accelerate electron/ion transport improved the Li⁺ transmission. By leveraging the combined properties of strong adsorption and high catalytic activity, the sulfur host effectively inhibited the shuttle effect and accelerated the redox kinetics of LiPSs. High-efficiency Li⁺ transmission, strong adsorption, and the efficient catalytic conversion activities of LiPSs in the heterostructure were experimentally and theoretically verified. The results indicate that the W₂N/Mo₂N cathode provides stable, and long-term cycling (over 2000 cycles) at 3 C with a low attenuation rate of 0.0196% per cycle. The design strategy of a twinborn nitride heterostructure thus provides a functionalized solution for advanced Li-S batteries.

The shuttle effect of lithium polysulfides (LiPSs) and uncontrollable lithium dendrite growth seriously hinder the practical application of lithium-sulfur (Li-S) batteries. To simultaneously address such issues, monodispersed NbN quantum dots anchored on nitrogen-doped hollow carbon nanorods (NbN@NHCR) are elaborately developed as efficient LiPSs immobilizer and Li stabilizer for high-performance Li-S full batteries. Density functional theory (DFT) calculations and experimental characterizations demonstrate that the sulfiphilic and lithiophilic NbN@NHCR hybrid can not only efficiently immobilize the soluble LiPSs and facilitate diffusion-conversion kinetics for alleviating the shuttling effect, but also homogenize the distribution of Li⁺ ions and regulate uniform Li deposition for suppressing Li-dendrite growth. As a result, the assembled Li-S full batteries (NbN@NHCR-S||NbN@NHCR-Li) deliver excellent long-term cycling stability with a low decay rate of 0.031% per cycle over 1000 cycles at high rate of 2 C. Even at a high S loading of 5.8 mg cm⁻² and a low electrolyte/sulfur ratio of 5.2 µL mg⁻¹, a large areal capacity of 6.2 mA h cm⁻² can be achieved in Li-S pouch cell at 0.1 C. This study provides a new perspective via designing a dual-functional sulfiphilic and lithiophilic hybrid to address serious issues of the shuttle effect of S cathode and dendrite growth of Li anode.

The Mn-based oxide cathode with enriched crystal phase structure and component diversity can provide the excellent chemistry structure for Na-ion batteries. Nevertheless, the broad application prospect is obstructed by the sluggish Na⁺ kinetics and the phase transitions upon cycling. Herein, we establish the thermodynamically stable phase diagram of various Mn-based oxide composites precisely controlled by sodium content tailoring strategy coupling with co-doping and solid-state reaction. The chemical environment of the P2/P'3 and P2/P3 biphasic composites indicate that the charge compensation mechanism stems from the cooperative contribution of anions and cations. Benefiting from the no phase transition to scavenge the structure strain, P2/P'3 electrode can deliver long cycling stability (capacity retention of 73.8 % after 1000 cycles at 10 C) and outstanding rate properties (the discharge capacity of 84.08 mA h g⁻¹ at 20 C) than P2/P3 electrode. Furthermore, the DFT calculation demonstrates that the introducing novel P'3 phase can significantly regulate the Na⁺ reaction dynamics and modify the local electron configuration of Mn. The effective phase engineering can provide a reference for designing other high-performance electrode materials for Na-ion batteries.

Combination of CO₂ capture using inorganic alkali with subsequently electrochemical conversion of the resultant ${\text{HCO}}_{\text{3}}^{\text{-}}$ to high-value chemicals is a promising route of low cost and high efficiency. The electrochemical reduction of ${\text{HCO}}_{\text{3}}^{\text{-}}$ is challenging due to the inaccessible of negatively charged molecular groups to the electrode surface. Herein, we adopt a comprehensive strategy to tackle this challenge, i.e., cascade of in situ chemical conversion of ${\text{HCO}}_{\text{3}}^{\text{-}}$ to CO₂ and CO₂ electrochemical reduction in a flow cell. With a tailored Ni-N-S single atom catalyst (SACs), where sulfur (S) atoms located in the second shell of Ni center, the CO₂ electroreduction (CO₂ER) to CO is boosted. The experimental results and density functional theory (DFT) calculations reveal that the introduction of S increases the p electron density of N atoms near Ni atom, thereby stabilizing *H over N and boosting the first proton coupled electron transfer process of CO₂ER, i.e., *+e^–+*H+*CO₂→*COOH. As a result, the obtained catalyst exhibits a high faradaic efficiency (FE_CO ∼ 98%) and a low overpotential of 425 mV for CO production as well as a superior turnover frequency (TOF) of 47397 h⁻¹, outcompeting most of the reported Ni SACs. More importantly, an extremely high FE_CO of 90% is achieved at 50 mA cm⁻² in the designed membrane electrode assembly (MEA) cascade electrolyzer fed with liquid bicarbonate. This work not only highlights the significant role of the second coordination on the first coordination shell of the central metal for CO₂ER, but also provides an alternative and feasible strategy to realize the electrochemical conversion of ${\text{HCO}}_{\text{3}}^{\text{-}}$ to high-value chemicals.

With the popularity and widespread applications of electronics, higher demands are being placed on the performance of battery materials. Due to the large difference in electronegativity between fluorine and carbon atoms, doping fluorine atoms in nanocarbon-based materials is considered an effective way to improve the performance of used battery. However, there is still a blank in the systematic review of the mechanism and research progress of fluorine-doped nanostructured carbon materials in various batteries. In this review, the synthetic routes of fluorinated/fluorine-doped nanocarbon-based (CF_x) materials under different fluorine sources and the function mechanism of CF_x in various batteries are reviewed in detail. Subsequently, judging from the dependence between the structure and electrochemical performance of nanocarbon sources, the progress of CF_x based on different dimensions (0D–3D) for primary battery applications is reviewed and the balance between energy density and power density is critically discussed. In addition, the roles of CF_x materials in secondary batteries and their current applications in recent years are summarized in detail to illustrate the effect of introducing F atoms. Finally, we envisage the prospect of CF_x materials and offer some insights and recommendations to facilitate the further exploration of CF_x materials for various high-performance battery applications.

Commercialization of perovskite solar cells (PSCs) requires the development of high-efficiency devices with none current density-voltage (J-V) hysteresis. Here, electron transport layers (ETLs) with gradual change in work function (WF) are successfully fabricated and employed as an ideal model to investigate the energy barriers, charge transfer and recombination kinetics at ETL/perovskite interface. The energy barrier for electron injection existing at ETL/perovskite is directly assessed by surface photovoltage microscopy, and the results demonstrate the tunable barriers have significant impact on the J-V hysteresis and performance of PSCs. By work function engineering of ETL, PSCs exhibit PCEs over 21% with negligible hysteresis. These results provide a critical understanding of the origin reason for hysteresis effect in planar PSCs, and clear reveal that the J-V hysteresis can be effectively suppressed by carefully tuning the interface features in PSCs. By extending this strategy to a modified formamidinium-cesium-rubidium (FA-Cs-Rb) perovskite system, the PCEs are further boosted to 24.18%. Moreover, 5 cm × 5 cm perovskite mini-modules are also fabricated with an impressive efficiency of 20.07%, demonstrating compatibility and effectiveness of our strategy on upscaled devices.

Herein, a stable and efficient CoS₂-ReS₂ electrocatalyst is successfully constructed by using the different molar ratios of CoS₂ on ReS₂. The size and morphology of the catalysts are significantly changed after the CoS₂ is grown on ReS₂, providing regulation of the catalytic activity of ReS₂. Particularly, the optimized CoS₂-ReS₂ shows superior electrocatalytic properties with a low voltage of 1.48 V at 20 mA cm⁻² for overall water splitting in 1.0 M KOH, which is smaller than the noble metal-based catalysts (1.77 V at 20 mA cm⁻²). The XPS, XAS, and theoretical data confirm that the interfacial regulation of ReS₂ by CoS₂ can provide rich edge catalytic sites, which greatly optimizes the catalytic kinetics and drop the energy barrier for oxygen/hydrogen evolution reactions. Our results demonstrated that interfacial engineering is an efficient route for fabricating high-performance water splitting electrocatalysts.

Electrocatalytic CO₂ reduction reaction to low-carbon alcohol is a challenging task, especially high selectivity for ethanol, which is mainly limited by the regulation of reaction intermediates and subsequent C–C coupling. A Cu-Co bimetallic catalyst with CN vacancies is successfully developed by H₂ cold plasma toward a high-efficiency CO₂RR into low-carbon alcohol. The Cu-Co PBA-V_CN (Prussian blue analogues with CN vacancies) electrocatalyst yields methanol and ethanol as major products with a total low-carbon alcohol FE of 83.8% (methanol: 39.2%, ethanol: 44.6%) at −0.9 V vs. RHE, excellent durability (100 h) and a small onset potential of −0.21 V. ATR-SEIRAS (attenuated total internal reflection surface enhanced infrared absorption spectroscopy) and DFT (density functional theory) reveal that the steric hindrance of V_CN can enhance the CO generation from *COOH, and the C–C coupling can also be increased by CO spillover on uniformly dispersed Cu atoms. This work provides a strategy for the design and preparation of electrocatalysts for CO₂RR into low-carbon alcohol products and highlights the impact of catalyst steric hindrance to catalytic performance.

Knowing the long-term degradation trajectory of Lithium-ion (Li-ion) battery in its early usage stage is critical for the maintenance of the battery energy storage system (BESS) in reality. Previous battery health diagnosis methods focus on capacity and state of health (SOH) estimation which can receive only the short-term health status of the cell. This paper proposes a novel degradation trajectory prediction method with synthetic dataset and deep learning, which enables to grasp the characterization of the cell’s health at a very early stage of Li-ion battery usage. A transferred convolutional neural network (CNN) is chosen to finalize the early prediction target, and the polynomial function based synthetic dataset generation strategy is designed to reduce the costly data collection procedure in real application. In this thread, the proposed method needs one full lifespan data to predict the overall degradation trajectories of other cells. With only the full lifespan cycling data from 4 cells and 100 cycling data from each cell in experimental validation, the proposed method shows a good prediction accuracy on a dataset with more than 100 commercial Li-ion batteries.