能源化学最新文献

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.

To achieve high energy density in lithium batteries, the construction of lithium-ion/metal hybrid anodes is a promising strategy. In particular, because of the anisotropy of graphite, hybrid anode formed by graphite/Li metal has low transport kinetics and is easy to causes the growth of lithium dendrites and accumulation of dead Li, which seriously affects the cycle life of batteries and even causes safety problems. Here, by comparing graphite with two types of hard carbon, it was found that hybrid anode formed by hard carbon and lithium metal, possessing more disordered mesoporous structure and lithophilic groups, presents better performance. Results indicate that the mesoporous structure provides abundant active site and storage space for dead lithium. With the synergistic effect of this structure and lithophilic functional groups (–COOH), the reversibility of hard carbon/lithium metal hybrid anode is maintained, promoting uniform deposition of lithium metal and alleviating formation of lithium dendrites. The hybrid anode maintains a 99.5% Coulombic efficiency (CE) after 260 cycles at a specific capacity of 500 mAh/g. This work provides new insights into the hybrid anodes formed by carbon-based materials and lithium metal with high specific energy and fast charging ability.

Carbazole moiety-based 2PACz ([2-(9H-carbazol-9-yl)ethyl]phosphonic acid) self-assembled monolayers (SAMs) are excellent hole-selective contact (HSC) materials with abilities to excel the charge-transfer-dynamics of perovskite solar cells (PSCs). Herein, we report a facile but powerful method to functionalize the surface of 2PACz-SAM, by which reproducible, highly stable, high-efficiency wide-bandgap PSCs can be obtained. The 2PACz surface treatment with various donor number solvents improves assembly of 2PACz-SAM and leave residual surface-bound solvent molecules on 2PACz-SAM, which increases perovskite grain size, retards halide segregation, and accelerates hole extraction. The surface functionalization achieves a high power conversion efficiency (PCE) of 17.62% for a single-junction wide-bandgap (∼1.77 eV) PSC. We also demonstrate a monolithic all-perovskite tandem solar cell using surface-engineered HSC, showing high PCE of 24.66% with large open-circuit voltage of 2.008 V and high fill-factor of 81.45%. Our results suggest this simple approach can further improve the tandem device, when coupled with a high-performance narrow-bandgap sub-cell.

With its generality and practicality, the combination of partial charging curves and machine learning (ML) for battery capacity estimation has attracted widespread attention. However, a clear classification, fair comparison, and performance rationalization of these methods are lacking, due to the scattered existing studies. To address these issues, we develop 20 capacity estimation methods from three perspectives: charging sequence construction, input forms, and ML models. 22,582 charging curves are generated from 44 cells with different battery chemistry and operating conditions to validate the performance. Through comprehensive and unbiased comparison, the long short-term memory (LSTM) based neural network exhibits the best accuracy and robustness. Across all 6503 tested samples, the mean absolute percentage error (MAPE) for capacity estimation using LSTM is 0.61%, with a maximum error of only 3.94%. Even with the addition of 3 mV voltage noise or the extension of sampling intervals to 60 s, the average MAPE remains below 2%. Furthermore, the charging sequences are provided with physical explanations related to battery degradation to enhance confidence in their application. Recommendations for using other competitive methods are also presented. This work provides valuable insights and guidance for estimating battery capacity based on partial charging curves.

Generally, layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles. While the arrangement of primary particles plays a very important role in the properties of Ni-rich cathodes. The disordered particle arrangement is harmful to the cyclic performance and structural stability, yet the fundamental understanding of disordered structure on the structural degradation behavior is unclarified. Herein, we have designed three kinds of LiNi_0.83Co_0.06Mn_0.11O₂ cathode materials with different primary particle orientations by regulating the precursor coprecipitation process. Combining finite element simulation and in-situ characterization, the Li⁺ transport and structure evolution behaviors of different materials are unraveled. Specifically, the smooth Li⁺ diffusion minimizes the reaction heterogeneity, homogenizes the phase transition within grains, and mitigates the anisotropic microstructural change, thereby modulating the crack evolution behavior. Meanwhile, the optimized structure evolution ensures radial tight junctions of the primary particles, enabling enhanced Li⁺ diffusion during dynamic processes. Closed-loop bidirectional enhancement mechanism becomes critical for grain orientation regulation to stabilize the cyclic performance. This precursor engineering with particle orientation regulation provides the useful guidance for the structural design and feature enhancement of Ni-rich layered cathodes.

The function of solid electrolytes and the composition of solid electrolyte interphase (SEI) are highly significant for inhibiting the growth of Li dendrites. Herein, we report an in-situ interfacial passivation combined with self-adaptability strategy to reinforce Li_0.33La_0.557TiO₃ (LLTO)-based solid-state batteries. Specifically, a functional SEI enriched with LiF/Li₃PO₄ is formed by in-situ electrochemical conversion, which is greatly beneficial to improving interface compatibility and enhancing ion transport. While the polarized dielectric BaTiO₃-polyamic acid (BTO-PAA, BP) film greatly improves the Li-ion transport kinetics and homogenizes the Li deposition. As expected, the resulting electrolyte offers considerable ionic conductivity at room temperature (4.3 × 10⁻⁴ S cm⁻¹) and appreciable electrochemical decomposition voltage (5.23 V) after electrochemical passivation. For Li-LiFePO₄ batteries, it shows a high specific capacity of 153 mA h g⁻¹ at 0.2 C after 100 cycles and a long-term durability of 115 mA h g⁻¹ at 1.0 C after 800 cycles. Additionally, a stable Li plating/stripping can be achieved for more than 900 h at 0.5 mA cm⁻². The stabilization mechanisms are elucidated by ex-situ XRD, ex-situ XPS, and ex-situ FTIR techniques, and the corresponding results reveal that the interfacial passivation combined with polarization effect is an effective strategy for improving the electrochemical performance. The present study provides a deeper insight into the dynamic adjustment of electrode-electrolyte interfacial for solid-state lithium batteries.

It is a challenge to coordinate carrier-kinetics performance and the redox capacity of photogenerated charges synchronously at the atomic level for boosting photocatalytic activity. Herein, the atomic Ni was introduced into the lattice of hexagonal ZnIn₂S₄ nanosheets (Ni/ZnIn₂S₄) via directional-substituting Zn atom with the facile hydrothermal method. The electronic structure calculations indicate that the introduction of Ni atom effectively extracts more electrons and acts as active site for subsequent reduction reaction. Besides the optimized light absorption range, the elevation of E_f and E_CB endows Ni/ZnIn₂S₄ photocatalyst with the increased electron concentration and the enhanced reduction ability for surface reaction. Moreover, ultrafast transient absorption spectroscopy, as well as a series of electrochemical tests, demonstrates that Ni/ZnIn₂S₄ possesses 2.15 times longer lifetime of the excited charge carriers and an order of magnitude increase for carrier mobility and separation efficiency compared with pristine ZnIn₂S₄. These efficient kinetics performances of charge carriers and enhanced redox capacity synergistically boost photocatalytic activity, in which a 3-times higher conversion efficiency of nitrobenzene reduction was achieved upon Ni/ZnIn₂S₄. Our study not only provides in-depth insights into the effect of atomic directional-substitution on the kinetic behavior of photogenerated charges, but also opens an avenue to the synchronous optimization of redox capacity and carrier-kinetics performance for efficient solar energy conversion.