ACS Applied Energy Materials最新文献

Hard carbon (HC) suffers from the issues of unsatisfactory sodium storage capacity and inferior rate performance, severely hindering its practical application. Enhancing the slope capacity of commercial HC is considered an optimal strategy for improving its rate performance. Bismuth metal is well-known for its exceptional rate capability and low-temperature performance. Herein, we report an effective approach for regulating the surface structure of commercial HC anodes by introducing bismuth nanoparticles and increasing oxygen functional groups. Particularly, polyvinylpyrrolidone self-assembled micelles were selected as the “core″ to facilitate the adsorption of Bi³⁺, which enables the nanocrystallization of the Bi-HC material to yield a carbon-coated Bi structure. Compared to commercial HC, the Bi-HC anode exhibits a significantly enhanced slope capacity (increase from 90 to 120 mAh g^–1 at 0.1 A g^–1) and rate capability (increase from 70 to 250 mAh g^–1 at 2 A g^–1) in the ether electrolyte. This surface regulation strategy offers a promising pathway for the development of high-performance HC anodes and the construction of efficient sodium-ion batteries.

Pairing high-voltage cathode materials with a lithium metal anode is recognized as a promising strategy for advancing the development of high-specific-energy batteries. Sulfone-based solvents were generally considered to have high oxidation stability due to the electron-withdrawing nature of their sulfonyl groups. Herein, an interesting phenomenon was observed in the LiPF₆/sulfolane electrolyte, sulfolane induces the decomposition of LiPF₆ at high potentials, ultimately affecting battery performance. Herein, a sulfone-based binary electrolyte system that weakens the sulfone-PF₆^– interaction and enhances the Li⁺-PF₆^– interaction was proposed. High-voltage lithium metal batteries with an LNMO cathode were achieved in a sulfone electrolyte with low-concentration LiPF₆. The binary electrolyte not only effectively suppresses the decomposition of LiPF₆ in the battery but also promotes the formation of a fluorine-rich cathode-electrolyte interface (CEI) and an organic/nonpolar mixed solid electrolyte interface (SEI) on the anode. The battery exhibits a capacity retention rate of 81% after 300 cycles at 0.5C/1C within the voltage range of 3.5–4.85 V.

High-capacity, low-cost alkaline metal aqueous redox flow batteries (ARFBs) are of great significance for large-scale energy storage. Among them, tin-based flow batteries have attracted increasing interest in recent years due to their high solubility of active materials and the advantages of less dendrite formation. However, the stability and reaction mechanism of Sn-based ARFBs still need to be further investigated. This study presents the design and demonstration of an alkaline Sn–Fe ARFB with K₄[Fe(CN)₆] and K₂Sn(OH)₆ in the catholyte and anolyte respectively, achieving a high-capacity and low-cost electrochemical energy storage system. The active material K₂Sn(OH)₆ exhibits a solubility above 3 M in an alkaline electrolyte at a temperature of 60 °C, resulting in an anolyte volume capacity of 321.6 Ah L^–1. It is determined using density functional theory computation that the binding energy between the surface of Sn and copper is higher than that of carbon-based materials, which leads to the formation of uniform small-particle crystal nuclei on the surface of the copper. Furthermore, the operando electrochemical tests prove that the solubility of SnO₂^2– is still one of the reasons that the energy efficiency cannot increase steadily with increasing concentration. A capacity retention of 74% is achieved after 5000 cycles with a stable voltage >1.3 V for the Sn–Fe ARFB. The demonstrated high-capacity and low-cost alkaline Sn–Fe ARFB shows superior performance in cycle life by alleviating the dendrite issue compared with Zn-based ARFBs, providing a promising Sn-based anolyte for high-energy metal-based ARFBs.

A material concept constructed of NiCo₂O₄, NiFe₂O₄, and carbon was designed and synthesized by using a two-step process involving hydrothermal and flaming deposition methods and was further applied for overall water splitting. In this study, the electrocatalytic activities of NCO/NFO/C in alkaline conditions were studied and compared to its single phase of NiCo-LDH, NiCo₂O₄, and NiFe₂O₄, including the materials characterization (e.g., scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman analyses). NCO/NFO/C was found as a 3D seaweed-like structure with an average particle size of 43.7 ± 2.1 nm. NCO/NFO/C electrocatalysts possess lower hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) overpotentials of 242 and 240 mV at 100 mA·cm^–2 as well as smaller Tafel slope values of 54 and 31 mV·dec^–1, respectively. Notably, NCO/NFO/C can be utilized as a bifunctional electrocatalyst for overall water splitting. NCO/NFO/C demonstrates a minimum cell voltage of 1.7 V at a current density of 100 mA·cm^–2. This work emphasizes the excellent electrocatalytic performances of NCO/NFO/C for overall water splitting as well as the facile synthesis technique.

Recently, molybdenum disulfide (MoS₂) quantum dots (QDs) have progressed efficiently for energy applications. This report demonstrates the preparation of MoS₂ QDs via a facile liquid exfoliation process. The developed QDs are thoroughly characterized and applied for energy conversion application in dye-sensitized solar cells and evidenced a high photovoltaic (PV) power conversion efficiency (PCE) of 8.30%. This study torches the usability of QDs for large-scale PV applications.

Perovskite solar cells (PSCs) with an inverted device configuration, commonly named as p-i-n architecture, hold significant promise for future commercialization owing to their scalable fabrication processes, reliable performance, and compatibility with a broad spectrum of tandem photovoltaics. Notably, the advancements in hole-transporting materials (HTMs) are pivotal in enhancing the power conversion efficiency (PCE) of inverted PSCs. This Spotlight article underscores the substantial progress in HTMs for p-i-n PSCs, particularly focusing on the design and application of self-assembled monolayer (SAM)-based molecules. The deposition of SAMs on transparent conductive oxides (TCOs) provides uniformly thin layers that minimize charge transport losses, thereby simultaneously improving open-circuit voltage and fill factors in PSCs. Further development of SAM molecular structures has enhanced their adsorption stability on TCOs, intrinsic molecular stability, and structural reliability at the perovskite-substrate interface. Finally, this Spotlight outlines prospective research directions and challenges of HTMs in PSCs.

Flexible perovskite solar cells (F-PSCs) have demonstrated remarkable potential for next-generation wearable platforms. Nonetheless, the reduction of open-circuit voltage (V_OC) at the interface within F-PSCs poses a significant barrier to improving the photoelectric conversion efficiency (PCE). Herein, we reported an effective “two birds with one stone” strategy by utilizing carbon dots (CDs) as a multifunctional treatment modulator to modify the SnO₂ electron transport layer (ETL) and buried interface. On the one hand, CDs were explored to passivate trap states associated with Sn dangling bonds and oxygen vacancies on SnO₂ surfaces through Lewis acid–base coordination, thereby enhancing the electron mobility of SnO₂ films and facilitating charge extraction from perovskite layers. On the other hand, the functional groups (including carboxyl, fluorine, and amino) on CDs enable the formation of coordination and hydrogen bonding with PbI₂, promoting the formation of high-quality perovskite films with reduced defect densities. The collective enhancements effectively mitigate trap-assisted charge recombination and interfacial energy loss, significantly reducing the device voltage deficit and enabling F-PSCs to attain a PCE of 22.97% with enhanced V_OC from 1.06 to 1.18 V. Notably, CDs-incorporated devices demonstrate exceptional operational durability, maintaining 83% of initial PCE after 400 h of continuous illumination (AM 1.5G) in an air atmosphere and retaining 81% PCE following 4000 cyclic bending tests (6 mm radius). This methodology establishes a robust framework for simultaneously enhancing both the efficiency and stability in FAPbI₃-based F-PSCs.

Spinel LiMn₂O₄ (LMO) is a promising fast-charging cathode material because its unique three-dimensional Li-ion diffusion channels offer favorable ionic diffusivity. However, LMO encounters rapid structural degradation at high current densities. To tackle this issue, we introduce K⁺ ions into the interstitial 16c sites to stabilize LMO, thereby achieving excellent fast-charging capability. The K-LMO retains 75% of its theoretical capacity at an ultrahigh current density of 1.48 A g^–1 (10 C, corresponding to a charging time of 5 min). Comprehensive characterizations demonstrate that the incorporation of K⁺ into LMO expands the LiO₄ space, strengthens the Mn–O bonds and suppresses the Jahn–Teller effect, leading to improved Li-ion mobility and enhanced stability of the diffusion channels. Additionally, the volume variation induced by cycling under a high charge state is efficiently suppressed through a solid-solution transition, thus preventing structural degradation against long-term cycling. Given this, this study presents an attractive candidate material for the cathode of fast-charging lithium-ion batteries.

Materials with both excellent magnetocaloric properties and high thermoelectric performance play a vital role in the invention of next-generation all-solid-state refrigeration technology. Herein, we investigate the interfacial reactions, thermoelectric and magnetocaloric properties of spark plasma sintered Bi_0.4Sb_1.6Te₃–Cr₅Te₆ composites, where a spatially confined ferromagnetic Cr₅Te₆ phase is embedded into the Bi_0.4Sb_1.6Te₃ thermoelectric matrix. The diffusion of Te element from Bi_0.4Sb_1.6Te₃ into Cr₅Te₆ as a result of concentration gradient during sintering leads to the formation of interfacial phase Cr₂Te₃ and Sb_Te antisite defects in the Bi_0.4Sb_1.6Te₃, both of which are detrimental to the thermoelectric and magnetocaloric performance of the composites. Sintering at a lower temperature effectively mitigates the interfacial reactions and suppresses Sb_Te antisite defects. Consequently, the room-temperature magnetocaloric and thermoelectric properties of the composites are concurrently optimized. Specifically, a high ZT value of 0.65 at 300 K and a relatively large magnetic entropy change ΔS_max = 0.33 J kg^–1 K^–1 at 5 T have been obtained for the Bi_0.4Sb_1.6Te₃-15 wt % Cr₅Te₆ composite sintered at 625 K. This research offers a promising pathway for the development of high-performance magnetocaloric and thermoelectric composite materials.

Developing robust catalysts for the oxygen evolution reaction (OER) is critical to advancing anion exchange membrane water electrolysis (AEMWE). This study introduces a novel strategy to improve the efficiency of Co-based catalysts by incorporating phosphorus doping (P-doping) through the simultaneous co-electrodeposition of Co and P. This P-doping approach not only significantly increases the number of active Co sites but also optimizes the oxidation state of Co, contributing to enhanced catalytic activity. The optimized catalyst demonstrates an overpotential of approximately 211 mV at 10 mA cm^–2 with a Tafel slope of 36.5 mV dec^–1 under half-cell conditions in 1 M KOH. In an AEMWE single-cell system, the catalysts shows a current density of 2100 mA cm^–2 at 1.8 V and 60 °C, with a degradation rate of 0.19 mV h^–1 over 1000 h at 1 A cm^–2. These results suggest that simultaneous P-doping is an effective strategy to enhance OER activity.