Batteries & Supercaps最新文献

Antimony selenide (Sb₂Se₃) is a promising electrode material for sodium-ion batteries (SIBs) due to its high theoretical capacity. However, volume expansion during sodiation/desodiation and the low conductivity of Sb₂Se₃ reduce the electrochemical performance. Herein, we synthesized Sb₂Se₃ nanorods (NRs) and combined them with multi-walled carbon nanotubes (MWCNTs) using one-step composite process to address these issues. MWCNTs can accommodate volume expansion and provide high conductivity. The fabricated Sb₂Se₃ NRs@MWCNT electrode exhibits improved cycle performance and cyclic stability without additional conductive carbons. The Sb₂Se₃ NRs@MWCNT electrode showed an enhanced specific capacity of 440 mAhg⁻¹ at a current density of 0.1 Ag⁻¹, compared to 220 mAhg⁻¹ for the Sb₂Se₃ NRs electrode. Additionally, it exhibited good stability at high current density. The in-situ electrochemical impedance spectroscopy (EIS) and Galvanostatic intermittent titration technique (GITT) were used to estimate the electrochemical properties and kinetics of Sb₂Se₃ NRs@MWCNT. These results showed that Sb₂Se₃ NRs@MWCNT have the potential as a conductive-free anode material in SIBs.

Single-crystalline (SC) Li-rich layered oxides have garnered significant attention due to their inhibited lattice oxygen release and reduced crack formation compared with polycrystalline (PC) counterparts. However, it raises a crucial question regarding the selection of prevailing lithium sources-Li₂CO₃ and LiOH⋅H₂O-for the solid-state synthesis of SC cathodes, which critically impacts the technical route and future development of SC materials. Herein, a series of SC Li-rich layered cathodes were synthesized using these two lithium sources. The SC materials prepared with LiOH⋅H₂O (LRO-H) exhibited larger grain sizes compared with those using Li₂CO₃ (LRO-C). This can be attributed to the lower phase transition temperature of the precursor to spinel phase, which promotes further SC growth during solid-state reactions. Furthermore, LRO-H demonstrated excellent electrochemical stability, whereas LRO-C exhibited superior initial capacities. To balance these attributes, a mixed lithium sources system (LRO-M) was proposed, showing superior Li⁺ diffusion kinetics and suppressed layered-to-spinel transformation, resulting in excellent rate performance and an extended battery lifespan. Altogether, these findings provide critical insights into the impact of lithium sources on the growth process, structural stability, and electrochemical properties of SC Li-rich layered cathodes, guiding the synthesis and design of next-generation cathode materials.

In recent years, the frequency of incidents related to the safety of electric vehicles (EVs) due to lithium-ion batteries has seen a troubling uptick, leading to a heightened focus on the safety of lithium-ion batteries (LIBs) as a critical area of research. After thorough analysis, this study contends that the root cause of the majority of safety incidents involving LIBs in the field is predominantly linked to reliability issues within the battery products themselves. This argument offers a more targeted perspective than a broad discussion on the safety concerns of LIBs. Reliability, in this context, is defined as the likelihood that a product will execute its intended function without error over a defined period and under specific conditions. The paper delineates the reasons why current safety testing standards are unable to entirely prevent LIB safety incidents, scrutinizes the multifaceted causes and testing methodologies associated with LIB unpredictive thermal runaways from reliability perspective, and aims to reduce the probability of battery field failure and electric vehicle fire incidents, with an emphasis on mtigating unpredictive fire accidents. This study advocates for a more aggressive research effort into the reliability of LIBs, parallel to the vigorous advancement of safety technologies for these batteries.

Cellulose-based separator exhibits excellent electrolyte affinity, thermal stability, and mechanical strength, which acts as a promising alternative to commercial polyolefin separators in lithium metal batteries (LMBs). Fiber size in cellulose-based separators plays a crucial role in determining their physicochemical structure and mechanical strength, as well as the electrochemical performance of corresponding LMBs. Herein, the fiber size in cellulose-based separators was first time regulated to optimize their mechanical stability and the related battery performance. The influences of fiber size in the separator on chemical structure, mechanical properties, surface morphology, electrochemical behavior were investigated in detail, in which the underlying mechanism between separator structure and the related performance was elucidated. As a result, the separator optimized by fiber size regulation exhibited excellent thermal stability under 180 °C, good tensile strengths of 6.0 MPa and Young's moduli of 315.9 MPa, superior room temperature ionic conductivity of 1.87 mS cm⁻¹, as well as significantly improved electrochemical performance of corresponding batteries. It can be concluded that structure optimization for cellulose-based separator through fiber size regulation is an effective and indispensable approach towards high safety and high performance LMBs.

Silicon anodes are a promising solution in all-solid-state batteries (ASSBs) due to minor lithium dendrite risk, high capacity, and low potential. Research on Si integration in ASSBs is still nascent, requiring a deep understanding of the interplay between electrode composition, structure, and performance. Here, we present the first study on 100 % Si nanowires integrated with Li₆PS₅Cl solid electrolyte (SE). The anodes are paper-like networks of aggregated Si nanowires produced by a slurry-free method without carbon/binders. Despite the lack of any conductor, the Si anodes provide >2.5 Ah/g capacity at a high mass loading of 1.7 mg/cm²(~5 mAh/cm²), demonstrating sufficient electric and ionic conductivities. Electro-chemo-mechanical properties of the electrodes over (de)lithiation were probed through electrochemical impedance spectroscopy, ex-situ microscopy, and in-operando pressure regulation measurements. The lithiated electrode/SE interface was found to be electrochemically stable. Cross-sectional microscopy at various states-of-charge confirmed the buffering effect of the anode porosity, resulting in the preservation of the electrode's thickness after the first lithiation but a considerable shrinkage during delithiation, producing cracking and formation of the new interface. Capacity remains constant for five cycles, then decreases linearly up to 40 cycles. This is attributed to repeated fracture of the anode/electrolyte interface and the corresponding impedance increase.

As an important part of the electrode material of lithium-ion batteries, the binder significantly affects the forming strength of the solid electrolyte interface (SEI), and also determines the mechanical properties and cycling stability. In the silicon anode, binder have greater effect in the chemical and electrochemical stability because of the volume of the silicon anode changes by more than 300 %. Thus, the development of functional new binders with enhanced properties is one of the keys to mitigating the instability of silicon anodes. This concept first briefly introduces the advantages and disadvantages of conventional electrode binders, then the current research progress of silicon anode binders is briefly summarized based on the different types of interaction forces of binders. Finally, we conclude the properties indicators of silicon anode binders with superior performance in batteries, and comment our previous work in detail.

Among the two-dimensional (2D) materials, layered hydroxides (LHs) stand out due to their chemical versatility, allowing the modulation of physicochemical properties on demand. Specifically, LHs based on earth-abundant elements represent promising phases as electrode materials for energy storage and conversion. However, these materials exhibit significant drawbacks, such as low conductivity and in-plane packing that limits electrolyte diffusion. In this work, we explore the synthetic flexibility of α-Co^II hydroxides (Simonkolleite-like structures) to overcome these limitations. We elucidate the growth mechanism of 3D flower-like α-Co^II hydroxyhalides by using in situ SAXS experiments combined with thorough physicochemical, structural, and electrochemical characterization. Furthermore, we compared these findings with the most commonly employed Co-based LHs: β-Co(OH)₂ and CoAl layered double hydroxides. While α-Co^II LH phases inherently grow as 2D materials, the use of ethanol (EtOH) triggers the formation of 3D arrangements of these layers, which surpass their 2D analogues in capacitive behavior. Additionally, by taking advantage of their anion-dependent bandgap, we demonstrate that substituting halides from chloride to iodide enhances capacitive behavior by more than 40 %. This finding confirms the role of halides in modulating the electronic properties of layered hydroxides, as supported by DFT+U calculations. Hence, this work provides fundamental insights into the 3D growth of α-Co^II LH and the critical influence of morphology and halide substitution on their electrochemical performance for energy storage applications.

Sodium-ion batteries present an appealing option for large-scale energy storage applications due to their high natural abundance and low production costs. However, the safety issue remains a major obstacle in current development, primarily owing to the use of liquid electrolytes (LEs), which can lead to leakage and combustion. To achieve both high energy density and enhanced safety, researchers are increasingly focusing on solid-state electrolytes (SSEs). Solid-state polymer electrolytes (SPEs) have garnered notable attention due to their superior mechanical flexibility and electrochemical stability. Nonetheless, traditional SPEs can also undergo combustion and decomposition under extreme conditions due to polymer inherent flammability. Therefore, it is imperative to conduct research and design flame-retardant SPEs in order to enhance their reliability and safety in practical applications. This review provides a comprehensive overview of the mechanisms underlying battery thermal runaway and offers guidance for designing batteries with enhanced safety. In addition to reviewing recent advancements in flame-retardant polymer solid-state sodium battery research, it also presents a systematic classification and introduction of studies on high-safety polymer electrolytes. Furthermore, it delves into diverse perspectives and approaches towards addressing the issue of safety in polymer sodium battery, ultimately outlining future research directions for this particular field.

The SEI is a crucial yet little understood component of lithium-ion batteries. The specific formation processes creating the SEI are still a matter of current research. In our paper, we analyse the electrochemical processes by incremental capacity analysis (ICA) and correlate these results with the evolved gas species and subsequent performance of the cells. 101 cells in total divided in three groups with different electrolytes performed a formation cycle. Afterwards gas-samples of half of the cells were extracted for analysis. We found a good correlation between variations of gas composition and noticeable ICA-data. Furthermore we explore correlations between formation and initial cell performance after a total of 10 cycles. Our results open new possibilities for a better understanding of formation processes.

Electrode manufacturing for electrochemical energy storage technologies often relies on hazardous fluorine-containing compounds and toxic organic solvents. To align with sustainability goals and reduce costs, there is a pressing need for water-processable alternatives. These alternatives can halve electrode processing costs and ease regulatory burdens. While progress has been made with water-processed graphite electrodes using eco-friendly binders, challenges persist for high-mass loading activated carbon (AC) electrodes. This study investigates the impact of modified aluminium current collectors on water-processed AC electrodes, focusing on compatibility, processability, and electrochemical performance. Various aluminium foils, including etched and carbon-coated types, were evaluated. The results show that modifications at the interface significantly improve the wetting properties and mechanical stability. Electrochemical tests revealed that carbon-coated aluminium provided the lowest internal resistance and highest rate capability due to intimate contact between the electrode components. In contrast, etched aluminium foil exhibited higher contact resistance and poorer performance. Ageing studies demonstrated that carbon-coated foils maintained better electrochemical performance over time, as the carbon layer reduced degradation reactions and contact resistance. These findings suggest that uniformly carbon-coated aluminium current collectors are the optimal choice for high-power electrochemical capacitors, balancing performance, sustainability, and cost-efficiency.