ACS Applied Energy Materials最新文献

CuI is a well-known thermoelectric (TE) material recognized for its p-type characteristics. However, the development of its n-type counterpart and the integration of both p- and n-type CuI in thermoelectric generators (TEGs) remain largely unexplored. In this study, we successfully tuned the thermoelectric properties of CuI by strategically incorporating Ag, enabling the synthesis of both p-type (Ag_0.2Cu_0.8I) and n-type (Ag_0.9Cu_0.1I) materials using a cost-effective, greener, and scalable successive ionic layer adsorption and reaction (SILAR) method. The p-type Ag_0.2Cu_0.8I exhibited a figure of merit (ZT) of 0.47 at 340 K, driven by a high Seebeck coefficient of 810 μV·K^–1. In contrast, the n-type Ag_0.9Cu_0.1I achieved an exceptional ZT of 2.5 at 340 K, attributed to an ultrahigh Seebeck coefficient of −1891 μV·K^–1. These superior thermoelectric properties make CuI-based materials attractive alternatives to conventional TE materials, such as Bi₂Te₃ and PbTe, which are limited by toxicity and resource scarcity. Furthermore, a prototype thermoelectric glazing unit (5 × 5 cm²) demonstrated a 14 K temperature differential, highlighting its dual functionality in power generation and building heat loss mitigation. These findings underscore the potential of low-cost CuI-based materials for advancing sustainable energy technologies.

The endurance of lithium–sulfur (Li–S) cells depends on the stability of lithium (Li) metal anodes and their consistent efficiency during extended Li dissolution and deposition cycles. Electrolytes containing Li[N(SO₂F)₂] (Li[FSA]) have shown potential in enhancing Li anode reversibility by promoting the formation of a favorable inorganic-rich solid-electrolyte interphase (SEI) on the Li metal electrode. However, the use of Li[FSA] as the primary electrolyte salt in Li–S batteries is hindered by the spontaneous side reactions of [FSA]⁻ anions with soluble lithium-polysulfides (Li₂S_x, 2 ≤ x ≤ 8). To overcome this challenge, we have developed a localized high-concentration electrolyte (LHCE) with reduced Li₂S_x solubility, composed of Li[TFSA_0.8LiFSA_0.2] ([TFSA]: [N(SO₂CF₃)₂]) binary salts dissolved in sulfolane (SL) and diluted by 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (HFE). This LHCE solution demonstrates superior stability of [FSA]⁻ anions, due to the restricted dissolution of Li₂S_x within the LHCE. We experimentally evaluated the critical factors affecting reversibility of Li dissolution/deposition in electrolytes containing Li[TFSA_0.8LiFSA_0.2]. Increased salt concentration, combined with HFE dilution, widens the reduction potential gap between the anion and Li⁺, which thermodynamically promotes anion reduction, controls SEI composition, and improves Li reversibility. We demonstrate the operation of a Li–S pouch cell under practical conditions with a high sulfur loading of 5.5 mg_(S) cm^–2 and an extremely low electrolyte/sulfur (E/S) ratio of 3.0 μL mg_(S)^–1. The battery delivers a high energy density of 280 Wh kg^–1. Our findings provide insights into the critical factors for achieving prolonged Li dissolution/deposition reversibility, particularly under practical Li–S pouch cell conditions, through electrolyte formulation design.

Band alignment (or band convergence) is a strategy suggested to provide improvements in the thermoelectric power factor (PF) of materials with complex bandstructures. The addition of more bands at the energy region that contributes to transport can provide more conducting paths and could improve the electrical conductivity and PF of a material. However, this can lead to increased intervalley scattering, which will tend to degrade the conductivity. Using the Boltzmann transport equation (BTE) and a multiband model, we theoretically investigate the conditions under which band alignment can improve the PF. We show that PF improvements are realized when intraband scattering between the aligned bands dominates over interband scattering, with larger improvements reached when a light band is brought into alignment. In the more realistic scenario of intra- and interband scattering coexistence, we show that in the light band alignment case, possibilities of PF improvement are present even down to the level where the intra- and interband scattering are of similar strength. For heavy band alignment, this tolerance is weaker, and weaker interband scattering is necessary to realize PF improvements. On the other hand, when interband scattering dominates, it is not possible to realize any PF improvements upon band alignment, irrespective of bringing a light or a heavy band into alignment. Overall, to realize PF improvements upon band alignment, the valleys that are brought into alignment need to be as electrically conducting as possible compared to the lower energy base valleys and interact as little as possible with those.

For the purpose of making high-value use of Chinese medicine waste, the preparation of derived biochar was studied and used as an electrode for supercapacitors (SCs). High-temperature KOH activation was used to convert the seed shells of discarded traditional Chinese medicine (Mubiezi) into graded porous carbon electrode materials, and the optimal electrode (MCSSAC-3) was obtained by optimizing the KOH addition ratio in this work. The MCSSAC-3 electrode obtained has a high specific surface area (1288.55 m² g^–1) and significantly higher specific capacitance of 302.29 F g^–1 at 0.5 A g^–1. The MCSSAC-3//MCSSAC-3 symmetric device has a high energy density of 11.13 Wh kg^–1 at a power density of 350 W kg^–1. In addition, even after 10,000 consecutive cycles, the MCSSAC-3//MCSSAC-3 symmetric device exhibits ideal capacitance retention of 87.16% at 10 A g^–1. This work offers an approach for the preparation of low-cost and high-performance SCs carbon-based electrodes from discarded traditional Chinese medicine.

Hydrogen has the potential to be a viable, clean, alternative energy source to nonrenewable fossil fuels. However, hydrogen’s use as an alternative fuel has been hindered by practical storage issues and safety concerns. Hence, it is of utmost importance to develop resourceful materials for hydrogen storage to achieve the real-world integration of hydrogen-powered fuel-cell vehicles. This review article summarizes recent innovations and developments using cutting-edge porous materials such as metal–organic frameworks (MOFs), zeolite imidazole frameworks (ZIFs), and covalent organic frameworks (COFs), which can effectively adsorb hydrogen owing to their structural versatility. We have emphasized recent innovations and developments in hydrogen storage materials and technologies that have shown benefits in both gravimetric and volumetric estimations. Ultimately, the goal of this Review is to outline key strategies for enhancing the hydrogen storage capabilities of porous materials. Finding ways to better store hydrogen could help address society’s environmental and energy needs as we transition from fossil fuels to cleaner alternatives like hydrogen.

Performance of metal halide perovskite solar cells depends largely on the perovskite film quality. Here, we demonstrate the impact of spin-coating temperature under anhydrous conditions on Pb-based mixed ion perovskite film morphology, crystal structure, optical properties, and their solar cell performance. The perovskite films prepared at spin-coating temperatures of ≤27 °C under anhydrous conditions showed pinhole-free and dense grain structures, while the perovskite films prepared at ≥35 °C showed formation of island/particles with void areas. This temperature dependence of the film formation mechanism can be explained by classical heterogeneous nucleation and growth theory with modified LaMer diagrams. In contrast, indistinguishable temperature dependence was found for charge carrier dynamics including electron and hole transfer rates and yield and charge carrier mobility inside the perovskite films. The highest solar cell performance was obtained for a solar cell based on a perovskite film prepared at around 25 (22–27) °C, suggesting that the solar cell performance is essentially controlled by the perovskite film morphology, but not by the charge carrier dynamics. These results also suggest that the process to preheat precursor solution is not required to obtain pinhole-free and dense perovskite films under anhydrous conditions. Furthermore, the optimum temperature to obtain pinhole-free perovskite films under anhydrous conditions was compared with the optimum temperature previously obtained under different humidity conditions, indicating that the optimum temperature rises with the increase in humidity.

Band alignment (or band convergence) is a strategy suggested to provide improvements in the thermoelectric power factor (PF) of materials with complex bandstructures. The addition of more bands at the energy region that contributes to transport can provide more conducting paths and could improve the electrical conductivity and PF of a material. However, this can lead to increased intervalley scattering, which will tend to degrade the conductivity. Using the Boltzmann transport equation (BTE) and a multiband model, we theoretically investigate the conditions under which band alignment can improve the PF. We show that PF improvements are realized when intraband scattering between the aligned bands dominates over interband scattering, with larger improvements reached when a light band is brought into alignment. In the more realistic scenario of intra- and interband scattering coexistence, we show that in the light band alignment case, possibilities of PF improvement are present even down to the level where the intra- and interband scattering are of similar strength. For heavy band alignment, this tolerance is weaker, and weaker interband scattering is necessary to realize PF improvements. On the other hand, when interband scattering dominates, it is not possible to realize any PF improvements upon band alignment, irrespective of bringing a light or a heavy band into alignment. Overall, to realize PF improvements upon band alignment, the valleys that are brought into alignment need to be as electrically conducting as possible compared to the lower energy base valleys and interact as little as possible with those.

Lithium-rich manganese layered (LMR) materials, utilizing the characteristics of both cation and anion redox, are promising cathodes for high-energy-density lithium-ion batteries. However, capacity fading and voltage decay pose challenges to their commercial applications. In this work, we employ chemical bonding to integrate Li₃VO₄ with Li_1.2Mn_0.6Ni_0.2O₂, leveraging their compatible properties to form a stable interface and address related challenges. An epitaxially grown Li₃VO₄ coating on Li_1.2Mn_0.6Ni_0.2O₂ crystals enhances stability at the electrode–electrolyte interface while also improving lithium-ion conduction. Additionally, the strong metal–oxygen bonds between the high-valence V element and Li_1.2Mn_0.6Ni_0.2O₂ effectively lower the surface oxygen activity, further preventing oxygen release and irreversible phase transitions. In the assembled half-cell tests, 3 wt % Li₃VO₄-coated Li_1.2Mn_0.6Ni_0.2O₂ exhibits excellent electrochemical performance. After 150 cycles at 200 mA g^–1, the discharge specific capacity reaches 188 mA h g^–1, with a capacity retention rate as high as 93%. Even under a high current density of 1000 mA g^–1, the discharge specific capacity remains at 128 mA h g^–1 after 200 cycles. This study highlights the significant impact of bonded lattice-matching materials, presenting a viable design strategy for developing high-performance LMR cathodes.

Solid-state lithium–metal batteries utilizing composite solid electrolytes show great potential for overcoming the safety and energy density issues associated with conventional Li-ion batteries. Nevertheless, the fundamental mechanism of Li-ion conduction in composite electrolytes is still unclear. In this study, Li_6.25Ga_0.25La₃Zr₂O₁₂-poly(ethylene oxide) (LLZO-PEO) composite electrolytes were fabricated by dispersing LLZO into a PEO matrix in different weight ratios to uncover the Li-ion conduction in both polymer- and ceramic-rich systems. The Li-ion transport in the LLZO-PEO composite was investigated by 2-probe AC impedance measurements at different temperatures. The in-depth impedance analysis based on conduction models confirms that Li-ions take different routes in composites depending on the LLZO ceramic content. For polymer-rich composites (up to ∼85 wt % LLZO), Li-ion conduction primarily occurred at the interfaces between PEO and LLZO, whereas above this threshold, conduction predominantly occurred through LLZO. The mechanistic insights into conduction behavior could be determinant in further optimizing the composite electrolytes for good cycling performance of solid-state lithium batteries.

Zinc ion batteries (ZIBs) are an intriguing option due to their safety, nonflammability, and environmental friendliness. However, the uncontrolled formation of Zn dendrites, which can lead to short circuits, limits their broader application. In this study, we designed an artificial interface layer on the surface of the Zn metal anode using a hydrothermal reaction in a fly ash suspension. This process created a zinc silicate (ZnSiO₃) thin film on the Zn surface, which helps control Zn ion accumulation and facilitates their diffusion, thereby enhancing the performance of the Zn anode. As a result, the symmetric cells achieved an impressive long-term lifespan of 1900 h at a current density of 0.5 mA·cm^–2, significantly outperforming bare Zn, which only lasted 68 h. Furthermore, the full cells demonstrated cycling stability with a capacity retention of 73% after 1000 cycles at a current density of 5 A·g^–1, compared to 53% for bare Zn. This work illustrates the potential of modifying Zn using fly ash, primarily composed of SiO₂, to create a ZnSiO₃ thin film layer. This strategy realizes the reuse of fly ash on the surface of Zn anode and promotes the further development of ZIBs.