The Zn anode suffers from severe dendrite growth and side reactions, which restrict its development in the realm of large-scale energy storage. Herein, in this study, we propose a method to create ...surface-microcracks in a Zn foil by 200 MPa cold isostatic pressing. The proposed pressing method can avoid the surface tip effect of Zn, and creates a subtly surface-microcracked zinc structure, providing more zinc ion transport channels, thereby effectively alleviating the dendrite growth and side reactions during the repeated Zn plating and stripping. Benefiting from these advantages, the 200 MPa Zn|Zn symmetric cell can achieve a long cycle life (1525 h) of 1 mA h cm
−2
at 2 mA cm
−2
. The 200 MPa Zn|VO
2
full cell can still maintain a capacity of 110 mA h g
−1
after 1000 cycles at 0.1 A g
−1
. In addition, assembled pouch cells also show excellent cycling stability. The proposed cold isostatic pressing method is compatible with large-scale production applications and provides an effective strategy for realizing high-performance zinc anodes for zinc-ion batteries.
200 MPa cold isostatic pressing creates a surface microcrack Zn foil for scalable and long life zinc anodes that increase zinc ion transport channels and improve zinc ion battery cycling performance.
The FeS2 has abundant reserves and a high specific capacity (894 mAh g−1), commonly used to fabricate Li‐FeS2 primary batteries, like LiMx‐FeS2 thermal batteries (working at ≈500 °C). However, ...Li–FeS2 batteries struggle to function as rechargeable batteries due to serious issues such as pulverization and polysulfide shuttling. Herein, highly reversible solid‐state Li‐FeS2 batteries operating at 300 °C are designed. Molten salt‐based FeS2 slurry cathodes address the notorious electrode pulverization problem by encapsulating pulverized particles in time with e− and Li⁺ flow conductors. In addition, the solid electrolyte LLZTO tube serves as a hard separator and fast Li+ channel, effectively separating the molten electrodes to construct a liquid–solid–liquid structure instead of the solid–liquid–solid structure of LiMx‐FeS2 thermal batteries. Most importantly, these high‐temperature Li–FeS2 solid‐state batteries achieve FeS2 conversion to Li2S and Fe at discharge and further back to FeS2 at charge, unlike room‐temperature Li‐FeS2 batteries where FeS and S act as oxidation products. Therefore, these new‐type Li‐FeS2 batteries have a lower operating temperature than Li‐FeS2 thermal batteries and perform highly reversible electrochemical reactions, which can be cycled stably up to 2000 times with a high specific capacity of ≈750 mAh g−1 in the prototype batteries.
This work reports Li–FeS2 secondary thermal batteries (240–300 °C) with a liquid–solid liquid structure. The liquid lithium anode and FeS2 slurry cathode are isolated using a U‐shaped LLZTO tube. The high battery reversibility is attributed to the reversible transition of Fe and Li2S to FeS2 at high temperatures and FeS2 pulverization. The FeS2 regeneration also avoids the production of polysulfides.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A lithium-ion battery has advantages such as high energy density and long calendar life, but it suffers from the risk of thermal runaway. Overcharge-induced thermal runaway accidents hold a ...considerable percentage. This article discovers that the slope of the dynamic impedance in the frequency band of 30-90 Hz turns positive from negative when the cell just starts to overcharge and proposes the theoretical explanation. Taking 70 Hz impedance as an example, the thermal runaway accident can be successfully avoided by cutting off the charging when the slope turns positive from negative during charging. The warning time is 580 s ahead of the thermal runaway. This feature is easy to identify and requires no complex mathematical models and parameters. Besides, the prediction method based on this feature can be conducted by using an online dynamic impedance measurement device designed by us, which is suitable for large-scale applications. Thus, the overcharge-induced thermal runaway accidents can be avoided.
Aqueous Zn‐ion batteries are plagued by a short lifespan caused by localized dendrites. High‐concentration electrolytes are favorable for dense Zn deposition but have poor performance in batteries ...with glass‐fiber separators. In contrast, low‐concentration electrolytes can wet the separators well, ensuring the migration of zinc ions, but the dendrites grow rapidly. In this work, we propose an electrolyte gradient strategy wherein a zinc‐ion concentration gradient is established from the anode to the separator, ensuring that the separator keeps a good wettability in low‐concentration areas and the zinc anode achieves dendrite‐free deposition in a high‐concentration area. By using this strategy in a common electrolyte, zinc sulfate, a Zn||Zn symmetric cell achieves 14 000 ultralong cycles (exceeding 8 months) at 5 mA cm−2 and 1 mAh cm−2. When the current is further increased to 20 mA cm−2, the symmetric cell could still run for over 10 000 cycles. Assembled Zn||NVO full cells also demonstrate prominent performance. At a high current of 16 mA cm−2, the NVO cathode with high loading (8 mg cm−2) still has a capacity of 58% after 1200 cycles. Overall, the gradient electrolyte strategy provides a promising approach for practical long‐life Zn anodes with the advantages of simple operation and low cost.
A novel gradient electrolyte strategy wherein a concentration gradient of zinc ions is constructed from the anode to the separator enables dense and dendrite‐free Zn deposition. The gradient electrolyte plays dual roles in keeping dense deposition on the zinc surface by the high‐concentration electrolyte containing carboxymethylcellulose and avoiding the water‐poor state of the GF separator by the low‐concentration electrolyte.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•Novel method for applying the venting acoustic signal to battery safety warning.•The effectiveness is studied by the thermal runaway experiment in a real battery cabin.•Combined with timely actions, ...this method can effectively suppress the thermal accumulation.•Recognition algorithms of the venting acoustic signal is constructed and achieves high accuracy.
Lithium-ion battery technology has been widely used in grid energy storage for supporting renewable energy consumption and smart grids. Safety accidents related to fires and explosions caused by LIB thermal runaway frequently occur, seriously threatening human safety and hindering further applications. Here we propose a safety warning method for MW-level LIB stations through venting acoustic signal, with the advantages of fast implementation, high sensitivity and low cost. To verify the effectiveness of the above method, an overcharge-induced thermal runaway experiment is conducted using commercial battery cells and modules in a real energy storage cabin. The results show that thermal runaway could be accurately and quickly detected through the venting acoustic signal, and timely actions can effectively suppress the development of thermal accumulation. Considering that many kinds of interference noise exist, a denoising method based on spectral subtraction is constructed after analysing the noise. To eliminate similar interference signals after denoising, an acoustic signal recognition classifier is built using the XGBoost model. The recognition accuracy can reach 92.31%. The above safety venting method based on venting acoustics provides a new approach to improve the safety level of grid energy storage.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Conventional DC-DC converters for renewable energy systems work in large duty cycle conditions, which will lead to the inductor saturations and decrease the system efficiencies and stabilities. In ...this brief, a new fifth-order boost converter, which can work in dual operating modes when different control technologies are adopted, is proposed. To obtain a wider conversion ratio, the required duty cycle for the proposed converter with synchronous controller is smaller than 0.333 while with interleaved controller is smaller than 0.5. Also, dual modes of this converter both have lower switches voltage stress. Then, the inductor saturation issues can be avoided and the system efficiencies and stabilities can be improved. Besides, the lower topological order and simple grounded structure of this converter are benefit to reduce the modeling complexity, topology volume and system noises. Detailed analyses, comparisons and prototype are implemented to study the improved conversion ratio, efficiency and power density of the proposed converter in-depth, and to validate its feasibilities for renewable energy applications.
Hydrogen reduction reaction (HER) and corrosion limit the long‐life cycle of zinc‐ion batteries. However, hydrophilic separators are unable to prevent direct contact between water and electrodes, and ...hydrophobic separators have difficulty in transporting electrolytes. In this work, an inorganic oxide‐based “hydrophobic–hydrophilic–hydrophobic” self‐assembled separator system is proposed. The hydrophobic layer consists of a porous structure, which can isolate a large amount of free water to avoid HER and corrosion reactions, and can transport electrolyte by binding water. The middle hydrophilic layer acts as a storage layer consisting of the GF separator, storing large amounts of electrolyte for proper circulation. By using this structure separator, Zn||Zn symmetric cell achieve 2200 h stable cycle life at 5 mA cm−2 and 1mAh cm−2 and still shows a long life of 1800 h at 10 mA cm−2 and 1mAh cm−2. The assembled Zn||VO2 full cell displays high specific capacity and excellent long‐term durability of 60.4% capacity retention after 1000 cycles at 2C. The assembled Zn||VO2 pouch full cell displays high specific capacity of 172.5mAh g−1 after 40 cycles at 0.5C. Changing the inorganic oxide materials, the hydrophobic–hydrophilic–hydrophobic structure of the separators still has excellent performance. This work provides a new idea for the engineering of water‐based battery separators.
An inorganic oxide‐based “hydrophobic–hydrophilic–hydrophobic” self‐assembled separator system is proposed. The hydrophobic layer consists of a porous structure, which can isolate a large amount of free water to avoid HER and corrosion reactions, and can transport electrolyte by binding water. The middle hydrophilic layer acts as a storage layer consisting of the GF separator, storing large amounts of electrolyte for long battery cycle life.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
AbstractLithium iron phosphate (LFP) batteries are widely utilized in energy storage systems due to their numerous advantages. However, their further development is impeded by the issue of thermal ...runaway. This paper offers a comparative analysis of gas generation in thermal runaway incidents resulting from two abuse scenarios: thermal abuse and electrical abuse. The study initially focuses on 13-Ah lithium iron phosphate single-cell batteries. Experiments were conducted to induce thermal runaway through both forms of abuse, analyzing the production and dispersion of H2 and CO gases in each case. It was observed that thermal abuse–induced thermal runaway resulted in higher gas concentrations and more pronounced fluctuations, whereas electrical abuse–induced thermal runaway exhibited lower gas concentrations and lower fluctuations. Subsequently, key materials and temperature variations at the positive and negative electrodes were investigated under both types of thermal runaway, revealing distinct differences that are identified as the primary reasons for the significant disparities in H2 and CO gas generation during the two thermal runaway conditions. The conclusions drawn in this paper advance the understanding of the mechanisms underlying H2 and CO gas concentration generation in thermal runaway scenarios.
Lithium-ion batteries are widely used in scalable electrochemical energy-storage stations because of their excellent characteristics. However, safety issues seriously hinder their further development ...and promotion. This paper proposes a safety warning method based on module-space air-pressure variation to provide warnings for battery thermal runaway (TR). TR is induced by different battery faults (overcharge, overheat), and the air pressure in the module space varies during the battery venting process. To verify the effectiveness of the TR warning by air-pressure variation signal, experiments were conducted in sealed and ventilated modules. The air pressures of the sealed and ventilated module spaces for batteries under 13 A (1C) overcharge-induced TR conditions were 19.3 hPa and 3.05 hPa higher, respectively, than the corresponding air pressures under normal conditions. Under 6.5 A (0.5C) overcharge-induced TR conditions, the air pressure of the sealed module space increased by 14.43 hPa. Under overheat-induced TR conditions, the sealed module space air pressure increased by 6.52 hPa. Upon detecting an air-pressure variation signal, immediate measures such as charge stoppage effectively prevent the occurrence of battery TR. The average time interval between the warning signal and battery TR was 473 s. This research provides a new way to enhance the safety of lithium-ion battery energy-storage stations.
•A novel method of applying module space air pressure variation signal to warn battery thermal runaway is proposed.•This method is based on the principle that the air pressure in module space varies after battery venting.•According to this method, the average time interval between the warning signal and thermal runaway was 473 seconds.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
