Batteries & Supercaps最新文献

The Cover Feature shows catalytic oxygen reduction (ORR) and oxygen evolution (OER) taking place in a liquid zinc–air battery system with the transfer of electrons and conversion between O₂ and OH⁻. The morphologies of the basic types of MOF catalysts for rechargeable zinc–air batteries are illustrated. Their porous structure and tunable chemical composition seem to be the main advantages for their use as electrocatalysts. Carbon-based materials derived from the MOF act as sacrificial templates with high activity, electrical conductivity and stability. In their Review (DOI: 10.1002/batt.202400402), Z. Sun and co-workers present three kinds of metal–organic skeleton bifunctional catalysts (pristine MOFs, MOF derivatives and composite derivatives) and show how they offer new possibilities for replacing noble metal catalysts.

The rheological properties of the slurry significantly influence the manufacturing process of solid-state battery cathode electrodes, affecting coating quality and the resulting cathode microstructure. The correlation between slurry attributes and final electrode characteristics is analyzed using particle size and solid content as key metrics. We perform coarse-grained molecular dynamics simulations of LiNi_0.8Mn_0.1Co_0.1O₂ and Li₆PS₅Cl composite electrodes, with simulated slurries closely fitting experimental viscosities, indicating the model's suitability for predicting slurry behavior. Then the microstructural properties of the dried and calendered electrodes are calibrated with in house experimental data. The simulation workflow is fitted completely using only two sets of force fields, one for the slurry and the other one for the dried state of the electrode. The effective electronic conductivities are contingent on the particle size, without showing significant limitation on cathode power capabilities. This comprehensive study highlights the intricate interplay between slurry solid content, microstructure design, and manufacturing processes in optimizing solid-state battery cell performance. Consistent slurry characteristics are crucial for uniform electrode coating while optimizing particle size and solid content improves electrode porosity. These findings provide valuable insights for enhancing solid-state battery electrode design and slurry-based manufacturing processes for the adaptation of already established scaling up technologies.

Graphene-like material prepared by a facile combustion synthesis was investigated as an electrode material in a microemulsion electrolyte. Notably, a stable voltage window of 2.2–2.4 V was achieved, surpassing previous reports for aqueous-based electrolytes on similar materials. The fabricated supercapacitor device exhibited a commendable specific capacitance values of 59 F g⁻¹ at 0.1 A g⁻¹ and 32 F g⁻¹ at 5 A g⁻¹, indicating its potential for high-current applications. Mechanistic examination revealed that the charge storage primarily relies on electric double-layer formation, with minor non-capacitive contribution from electrode surface functionalities and the supporting electrolyte. Further analysis showed significant capacitive contributions of 85 % at 2.2 V and 67 % at 2.4 V, underscoring the dominance of the capacitive process. The fabricated supercapacitor's stability indicated a decrease as the non-capacitive process intensified, suggesting that electrode surface functionalities predominantly contribute to cell deterioration at elevated potentials. These results highlight the potential efficacy of microemulsion electrolytes in energy storage applications.

Carbon paper is widely utilized in supercapacitors primarily for its notable attributes, including high specific surface area, commendable electrical conductivity, and excellent chemical stability. Then investigate the effect of carbon paper with different porosities as supercapacitor substrates on the electrochemical performance of electrodes. Meanwhile, tungsten oxide is grown on the surface of carbon paper using the hydrothermal method to test the electrochemical performance of the composite electrode. The prepared carbon paper and oxygen-deficient tungsten oxide (WOx) composite electrode (CP@WOx) exhibit an area-specific capacitance of 915.8 mF/cm² at a current density of 5 mA/cm². In addition, the electrode exhibits good cycling stability. After 20,000 cycles, the capacitance remains 104.1 % of the original capacity at 50 mA/cm² current density. Solid-state symmetric supercapacitors assembled using CP@WOx electrode exhibit excellent performance in terms of surface energy density of 6.25 μWh/cm² (at a power density of 0.6 mW/cm²) and maintain 100.4 % of their original capacity after 7000 charge/discharge cycles. Relying on the higher productivity advantage of centrifugal spinning technology over electrostatic spinning technology and other preparation processes, this study develops a new way of thinking for the large-scale production of composite electrode materials, which has more considerable potential for large-scale development.

Alternative configuration of lithium cell exploits electrode and polymer electrolyte cast all-in-one to form a membrane electrode assembly (MEA), in analogy to fuel cell technology. The electrolyte is based on polyethylene oxide (PEO), lithium bis-trifluoromethane sulfonyl imide (LiTFSI) conducting salt, LiNO₃ sacrificial film-forming agent to stabilize the lithium metal, and fumed silica (SiO₂) to increase the polymer amorphous degree. The membrane has conductivity ranging from ~5×10⁻⁴ S cm⁻¹ at 90 °C to 1×10⁻⁴ S cm⁻¹ at 50 °C, lithium transference number of ~0.4, and relevant interphase stability. The MEA including LiFePO₄ (LFP) cathode is cycled in polymer lithium cells operating at 3.4 V and 70 °C, with specific capacity of ~155 mAh g⁻¹ (1 C=170 mA g_LFP⁻¹) for over 100 cycles, without signs of decay or dendrite formation. The cell exploiting the MEA shows enhanced electrochemical performance as compared with the one using simple polymeric membrane stacked between cathode and anode. Furthermore, the MEA reveals the key advantage of possible scalability and applicability in roll-to-roll systems for achieving high-energy lithium metal battery, as demonstrated by pouch-cell application. These data may trigger new interest on this challenging battery exploiting the polymer configuration for achieving environmentally/economically sustainable, and safe energy storage.

Photo-assisted supercapacitor is a promising smart device component for achieving both energy conversion and storage. The photo-assisted functionality in a supercapacitor is realized through the choice of photo responsive electrode material under suitable illumination conditions. The well-known electrochemically active electrode materials are wide band gap semiconductors which absorb strongly in UV light. However, most of the prior studies on photo-assisted supercapacitors used visible light. Herein, we present a transparent TiO₂/MoO₃ bi-layer heterojunction made by simple solution process as an efficient electrode for photo-assisted supercapacitors under UV light illumination. The electrochemical performance of the electrode is significantly enhanced even with a less intense (0.05 mW/cm²) UV light, compared to dark as well as the single layer electrode under same illumination condition. The highest areal capacitance of 63.25 mF/cm² at 0.1 mA/cm² is achieved, that surpasses most of the recent relevant reports. The synergetic effect of UV illumination and the built-in potential at the type II heterojunction interface encourages ion insertion and better collection of the photo-generated carriers. The unique bi-layer design also leads to better rate capability features. Thus, the work presents a new prospect for the development of transparent energy storage devices to be used in future smart technologies.

Structural metal-organic framework (MOF)-based pseudocapacitive components have exhibited significant potential for supercapacitors. Herein, a highly functioning vertically aligned La(OH)₃@Cu(OH)₂/Co(OH)₂ core-shell composite was in situ yielded from the template Co MOF-74 frameworks on the nickel foam (Co MOF/NF) via a dual approach of heterointerfacing and structural engineering. The sacrificial template Co MOF/NF microrods were converted into binary hydroxide Cu(OH)₂/Co(OH)₂/NF (Cu/Co/NF) junction with spatial nanogranule self-assembled microrods-like structure through a cation exchange reaction. Subsequently, the binary hydroxide Cu/Co junction was employed as a backbone to stabilize La(OH)₃ species via an electrodeposition process, forming a heterostructural La(OH)₃@Cu/Co/NF (La@Cu/Co/NF) core-shell composite. Preliminary electrochemical analysis demonstrates the efficiency of the binder-free La@Cu/Co/NF core-shell electrode, revealing a specific capacitance value of 874.8 F g⁻¹ at 1 A g⁻¹ and high rate ability (65.2 % capacitance retention at 30 A g⁻¹). Hence, it combines rich electrochemical reactive sites for Faradaic redox reactions and the favorable synergistic effect of integrated constituents. The configured La@Cu/Co/NF//AC asymmetric supercapacitor (ASC) device boasts a maximum voltage window of 1.55 V, acquiring an energy density of 43.9 Wh kg⁻¹ at 775 W kg⁻¹. Besides, the device maintains a capacitance retention rate of 76.4 % even after enduring 11,000 charge-discharge cycles, suggesting good long-term durability.

The cycling performance of high-loading Li−S batteries is still puzzled by the serious shuttle effect of polysulfides. Modifying the commercial separator with polysulfide anchoring materials has been demonstrated as an economical and effective approach to block the polysulfide shuttle. Herein, a cobweb-like polymer polysulfide-blocking layer has been constructed via crosslinking between lithium polysilicate (LP) inorganic oligomer and tannic acid (TA) dendritic polymer. Owing to the strongly polar Si−O and Si=O bonds in LP, the spider-web polymer possesses robust affinity towards polysulfides, indicated by the theoretical calculations. Dendritic polymer TA as the skeleton contributes to effectively exposing the abundant polar functional groups to powerfully capture the polysulfides. As a result, the cycling stability of high-loading Li−S batteries has been obviously improved. The Li−S battery with sulfur loading of 3.44 mg cm⁻² can stably cycle 100 cycles with a high capacity of 685.1 mAh g⁻¹ and columbic efficiency of 99.82 %. Even the sulfur loading increases to 7.15 mg cm⁻², the Li−S battery can still deliver a high areal capacity of 5.26 mAh cm⁻² after 50 cycles.

Sustainable sodium-ion batteries (SIBs) have gained tremendous attention; however, the large-sized Na⁺ poses serious challenges on the development of inorganic-based cathodes. To overcome the issues, metal–organic electrode materials are appealing because they combine attractive characteristics of organic redox centers (e. g., flexibility, highly reversible redox properties, fast kinetics (regardless of size and charge of guest ions), structural/redox tunability, and resource abundance) with structural stability arising from metal-ligand coordination. Herein, a one-dimensional copper−benzoquinoid coordination polymer (CP), [CuL(Py)₂]_n, (LH₄=1,4-dicyano-2,3,5,6-tetrahydroxybenzene, Py=pyridine) is investigated as cathode for SIBs. As opposed to most CPs reported for SIBs which possess high porosity and surface area, this close-packed CP can deliver discharge capacity as high as 277 mAh g⁻¹ at 2C (~523 mA g⁻¹), and at extremely high rates of 50C and 300C (~13 and 78 A g⁻¹), reversible capacities of 131 and 74 mAh g⁻¹ still can be delivered, respectively. The transport kinetics of Na⁺ in [CuL(Py)₂]_n is found to be even faster than that of Li⁺ despite the close-packed structure. The mechanistic and kinetic studies have been performed. The findings gained in this work undoubtedly unravel a potential design strategy for high-performance metal–organic electrode materials for emerging post-Li-ion batteries.

Sodium-ion batteries (SIBs) have evoked much attention, benefiting from the advantages of low cost, high safety and excellent performance at low temperature. Especially, Na₄Fe₃(PO₄)₂P₂O₇ (NFPP) cathode is considered to be one of the best candidates for SIBs cathode with abundant resources and long-term cycling stability. However, the impurities of NaFePO₄ (NFP) and Na₂FeP₂O₇ (NFPO) formed synchronously with NFPP which restrict the further application of NFPP. It is meaningful to clear the formation process and regulate the contents of NFP and NFPO. Therefore, NFPP cathodes with different contents of NFP and NFPO were prepared through high energy ball milling cooperated with post-heat treatment by controlling the Fe concentration in reactants. The NFPP-2.85 showed the best electrochemical performance because of the high content of NFPP and transition zone between NFPP and NFPO which fasts the Na⁺ transport kinetics. When employed as cathode for SIBs, the as-prepared NFPP-2.85 showed a specific capacity of 111.8 mAh g⁻¹ at 0.1 C and maintained at 68.9 mAh g⁻¹ even at 100 C. The retention ratio was as high as 93.6 % after 1500 cycles at 20 C, implying superior high rate-long term cycling stability. This work provides a new way for impurities regulation and the improvement of NFPP electrochemical performance.