Journal of Power Sources最新文献

Understanding internal processes before and during thermal runaway (TR) is essential for designing safe battery systems. This study aims to experimentally investigate and model the influence of temperature gradients on the initiation of TR and its propagation within lithium-ion cells. Local overheating abuse tests in an autoclave are performed with constant and stepwise heating profiles to apply extreme thermal inhomogeneities to the cells. The internal TR propagation is measured in situ with built-in thermocouples at different positions within the electrode-separator stack and on the surface of the cells. Results show the influence of the layered structure on in-plane and through-plane TR propagation. Further, the stepwise overheating procedure discloses the considerable influence of temperature gradients and local decrease in reactivity due to the consumption of reactants with a measured local temperature of 347 °C inside the cell before TR. Additionally, a simplified TR model with two Arrhenius equations is parameterized using accelerating rate calorimetry (ARC) and validated with local overheating experiments. In this regard, the influence of mass loss is also examined. The results demonstrate that the simplified approach is sufficient for considering thermal inhomogeneities and can significantly improve simulations compared to utilizing fixed trigger temperatures obtained directly from ARC experiments.

The presented study strives to further the knowledge of materials for battery technologies based on the first alkali metal ions: lithium, sodium, and potassium. The primary aim of the discussed research was to assess the possibility of creating a universal anode material for those three battery chemistries and investigate the insertion process of different ions in that material. The proposed active material is shungite, a naturally occurring carbon-rich mineral whose turbostratic structure was demonstrated by TEM microscopy. The lithium and potassium-based batteries achieved a similar initial capacity of ∼160 mAh g⁻¹ and were able to retain 147 and 133 mAh g⁻¹ after 50 cycles, respectively. The discharge capacity of sodium battery was only 55 mAh g⁻¹ but the capacity retention and cycle stability were satisfactory, which indicates that the low value is related to the mixed mechanism of sodium ion insertion/adsorption in the macroporous material instead of the degradation of the sodiated material over time. It was revealed that the purification process assisted with an ultrasound treatment develops the specific surface area of shungite and removes sulfur-based impurities. Such treatment significantly lowers the total cell impedance and enhances the battery cycling stability.

Cross-linked poly (4,4′-(diphenyl ether)-5,5′-bibenzimidazole) (OPBI) membranes are fabricated via an in-situ casting process using Ethynyl-grafted OPBI as the matrix and 4,4′-diazido-2,2′-stilbenedisulfonic acid disodium salt tetrahydrate (DSDAD) as the cross-linker, for high temperature proton exchange membrane fuel cell applications. The Ethynyl-grafted OPBI is synthesized through an N-substitution reaction with propargyl bromide to introduce cross-linkable sites into the OPBI backbone. Cross-linking is achieved through azide-alkyne click reactions and the dimerization of ethynyl groups, resulting in membranes that exhibit enhanced oxidative stability and mechanical properties compared to the linear OPBI membrane. Additionally, these membranes demonstrate increased proton conductivity, attributed to the unique characteristics of DSDAD as the cross-linker, which forms multiple hydrogen bonds within the polymer matrix and generates triazole linkages through the cross-linking reaction. With these improvements in various properties, the C_E-OPBI-2, featuring an optimum degree of cross-linking attains a power density 27 % higher than that of the unmodified OPBI membrane.

Compared with flammable liquid electrolytes, solid state electrolytes show promising potential for lithium-ion batteries with high safety and high energy density simultaneously due to their high thermal stability, mechanical strength, excellent chemical and electrochemical stability. Solid polymer electrolytes are an attractive choice to achieve high energy density due to their thinness and good manufacturability. However, traditional solid polymer electrolytes typically need to operate at above 60 °C due to the insufficient room-temperature ionic conductivity, thereby limiting its practical application in common room temperature lithium-ion batteries. Here, we report a novel design of polyoxymethylene (POM)-based solid polymer electrolytes for high-performance room-temperature all-solid-state lithium batteries. This design includes POM and lithium bis(trifluoromethylsulfonyl)amine (LiTFSI), which offers the similar structure to polyethylene oxide based solid electrolyte while with shorter chain segments to achieve higher ionic conductivity (2.8 × 10⁻⁴S cm⁻¹) and mechanical strength at room temperature. As a result, lithium dendrites can be efficiently suppressed, and symmetrical Li-Li cells have demonstrated more than 300 h of cycling at 0.05 mA cm⁻². The wide electrochemical stability window of 4.75 V also enables broader application for full cells. All-solid-state lithium batteries fabricated with POM/LiTFSI exhibit excellent cycling stability for 150 cycles at 0.2 C rate at room temperature. The design breaks through the useable temperature limit of solid polymeric electrolytes and broaden their application in all-solid-state lithium batteries.

In this study, a cost-effective, eco-friendly deep eutectic solvent (DES), comprising acetamide, sodium perchlorate, and zinc chloride serves as an innovative electrolyte for dual ion batteries. Notably, the DES exhibits a broad electrochemical stability window, self-extinguishing behavior, and great resilience in low temperatures. The interplay between the electrolyte components is being thoroughly scrutinized, with a particular focus on the benefits of adding a co-solvent to the DES. This addition prevents unwanted reactions and zinc dendrite growth through the formation of a solid electrolyte interphase (SEI) layer, ultimately leading to enhanced coulombic efficiency and cyclic stability. The electrochemical performance of zinc ion batteries (ZIBs) using a Prussian blue analog (K–MnHCFe) as cathode is being examined in the dual-ion DES electrolyte. The device displays a discharge capacity of 76.4 mAh g⁻¹ at 0.3 A g⁻¹ and a maximum energy density of 111.7 Wh kg⁻¹ at a power density of 437.5 W kg⁻¹. Furthermore, it retains 65 % of its initial specific capacity even after 3000 cycles at 0.5 A g⁻¹. It is noteworthy that the ZIB device with dual-ion DES operates normally in temperatures as low as −20 °C, outperforming traditional cells with aqueous electrolytes.

In the quest for high-energy-density lithium metal batteries (LMBs), the stabilization of lithium (Li) metal anodes during fast charging remains a formidable challenge. In this study, a novel copolymer, Poly(methyl methacrylate-co-styrene) (namely PMS) is synthesized and blended with Poly(vinylidene fluoride) to fabricate a porous gel polymer electrolyte (GPE, namely PMS-PVDF) through the nonsolvent-induced phase separation technique, which significantly enhances the electrochemical stability and fast-charging capabilities of LMBs. The developed GPE exhibits a high ionic conductivity of 5.62 mS cm⁻¹, thereby reducing the formation of detrimental Li dendrites and leading to over 400 h stripping/plating process at 0.5 mA cm⁻². Extensive electrochemical tests show that the LMBs with the obtained PMS-PVDF GPE achieve exceptional cycle stability over 600 and 1000 cycles at the C-rates of 0.5 and 3 C, respectively, outperforming traditional electrolytes. Furthermore, the ultra-stability of the quasi-solid-state electrolyte is demonstrated in a 375 mAh pouch cell setup, suggesting an essential trait for the practical application of high-power devices. This work marks a pivotal contribution to the field of energy storage, delivering insights and a clear methodology that pave the way for the development of next-generation LMBs poised for commercial viability.

Spinel LiNi_0.5Mn_1.5O₄ (LNMO) has gained significant attention as a promising cathode material for lithium-ion batteries due to its high working voltage (>4.7 V) and energy density. However, challenges such as electrolyte decomposition-induced material interface erosion and transition metal dissolution under high operating voltage hinder its commercial use. In this study, a thin and uniform Sm₂O₃ layer has been successfully deposited on the surface of LNMO using a wet chemical method. A comprehensive investigation of surface morphology, crystal structure, and electrochemical performance of the modified LNMO is conducted. The results demonstrate that the Sm₂O₃ surface modification acts as a robust multifunctional protective layer, effectively shielding against hydrofluoric acid-induced chemical attack and enhancing the migration efficiency of lithium ions. Notably, the capacity retention rate of LNMO@Sm₂O₃ (3 wt%) remains up to 88 % after 280 cycles, significantly surpassing the uncoated counterpart. The coated material exhibits a capacity of 114 mAh g⁻¹ even under 10 C rate conditions. Moreover, the AC impedance values and manganese dissolution of the modified material in the organic electrolyte are considerably lower than those of the uncoated counterpart. Theoretical calculations strongly support the experimental findings, revealing higher Mn vacancy formation energy and density of states at the Fermi energy level for the Sm₂O₃-modified electrodes. This research contributes to the field of surface modification and paves the way for further enhancements in the electrochemical performance of other high-voltage manganese-based lithium-ion batteries (LIBs).

The trade-off between proton conduction and vanadium permeability is a great challenge for ion conductive membrane to achieve high vanadium redox flow battery (VRFB) performance. Herein, the quinone convertible phenolic hydroxyl group side chain is proposed to endow Donnan effect and continuously narrow ion conductive channel to improve H⁺/V^n + selectivity. Uniquely, phenol can be chemically converted into quinone of lower electronegativity in-situ in the strong acidic VRFB environment, which greatly increases the Zata potential (from 2.6 to 10.2 mV) and Donnan effect to repel vanadium ions. A high phenol hydroxyl group capacity with 5.43 mmol g⁻¹ can be achieved owing to the swelling restriction by the hydrogen bonding crosslinking between quinone and benzimidazole, which constructs small but densely distributed ion clusters and continuously narrow ion conductive channels for selective proton conduction. The quinone type polybenzimidazole membrane (PBIPhQ-5.43) presents low area resistance and vanadium permeability (0.25 Ω cm² and 1.3 × 10⁻⁹ cm² s⁻¹, 13.8 % and 99.6 % decreased, respectively, compared with that of Nafion 212). The VRFB exhibits excellent balance between energy efficiency (83.1 %) and discharge capacity decay (0.29 %/cycle) at 100 mA cm⁻², far superior to that of Nafion 212 membrane (75.1 %, 0.71 %/cycle).

Fast charging and all-climate electrochemical behaviors are two of the most important issues of olivine cathodes for lithium ion batteries (LIBs) owing to inferior Li⁺ and electron conduction at a high current density or low temperature. Taking Mn-containing olivine cathode (LiFe_0.8Mn_0.2PO₄, LFMP) as an example, herein, we report a facile interconnected, hierarchically porous and highly conductive framework design strategy to construct an advanced bulk LFMP@graphene hybrid, realizing superior fast charging capability and wide temperature performance (−20∼80 °C). Such hybrids not only offer well-interconnected and highly conductive graphene networks, but also possess hierarchical porous interiors where the former ensures high-efficiency charge transfer between active components while the latter facilitates Li⁺ diffusion. Benefiting from these advantages, the obtained hybrids deliver superior rate capability (85.0 mAh g⁻¹ up to 20C) and high capacity retentions of 94.1 % after 3000 cycles at 10C (50 °C), and 91.7 % after 500 cycles at 5C (80 °C), and 93.6 % after 1300 cycles at 1C (−20 °C). This work provides an efficient strategy to design practical olivine cathode at the material level for fast charging and all-climate LIBs.

Sulfur (S) doping is recognized as a robust strategy to improve the Na⁺ storage property of carbon electrode. However, designing novel and effective S-doping method that combines safety, economy, and high doping levels remains urgent and challengeable. Herein, magnesium (Mg) salt is found to present an effective S-fixation role, including the Mg–S strong interaction promoted thermal stability of S atoms and the secondary S doping of MgSO₄-derived SO₂. Based on this S fixation strategy, a novel hard carbon with high S doping level of 16.5 wt% is fabricated by using sulfonated magnesium gluconate as raw material. This S-doped carbon anode delivers a high reversible Na storage capacity of 424 mAh g⁻¹ at 0.1 A g⁻¹, and after 1000-time cycling test under 1 A g⁻¹, the specific capacity remains 249 mAh g⁻¹ with a capacity retention rate of 90 %.