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In order to improve the preparation process and practical process of magnetic refrigerant, a method of accelerating phase formation by cold compression plastic deformation at room temperature was proposed. The grain structure, phase composition and magneto-thermal effects of La0.6Pr0.4Fe10.7Co0.8Si1.5 alloy were systematically studied. The results show that with the increase of compression ratio, the number of grains per unit area increases and the grain size is uniform. Compared with the uncompressed sample, the proportion of magnetothermal phase increases after annealing under the same conditions. When the compression rate is 30%, the ratio of 1∶13 phase after 3 days annealing is 92.68%(volume fraction), and the pre deformed sample is obviously better than the undeformed sample.After annealing for 3 days, the Curie temperature (TC) of 30% pre-deformed La0.6Pr0.4Fe10.7Co0.8Si1.5 is 289 K, and the magnetic entropy change (ΔSmax) is -7.1 J/(kg·K) under 2 T magnetic fields.The suitable Curie temperature and value of ΔSmax make it an attractive potential candidate for the room temperature magnetic refrigeration application.

Lithium salts exert a great influence on the electrochemical performance of lithium metal batteries. Dissociated Li-ions present rapid transfer dynamics through solvation with a solvent in liquid batteries or complexation–decomplexation with a polymer in solid batteries. However, the effect of the anion on the properties of batteries is still unclear. Herein, lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) and lithium difluoro(oxalato)borate (LiDFOB) are selected to investigate the working mechanism of anions in solid and liquid systems. LiTFSI demonstrates superior electrochemical performance in solid batteries (stable cycling for 2000 h at 0.1 mA cm−2), while LiDFOB exhibits better cycling performance in liquid batteries (the capacity retention reaches 94.8% after 500 cycles at 1C). DFT calculations are conducted to investigate the discrepancy and suggest that TFSI− presents higher binding energy with PEO, indirectly proving the important role of the anion in facilitating the transfer of Li-ions in solid systems. As for liquid batteries, XPS and in situ optical microscope analyses show that DFOB− is conducive to the generation of robust interfaces and inhibits the continuous decomposition of the electrolyte. Therefore, it can be innovatively deduced that the properties of solid batteries are determined by Li-ion transfer adjusted by the anion, while the liquid battery performance is decided by the electrode/electrolyte interface stability regulated by the anion. [ABSTRACT FROM AUTHOR]

All-solid-state lithium batteries (ASSLBs) are increasingly regarded as one of the next-generation energy storage technologies, offering good abuse tolerance, a wide operating temperature range, and a simplified battery system suitable for automotive applications. In the pursuit of cost-effectiveness and battery thermal stability, LiFePO4 (LFP) has recently attracted widespread attention in both industry and academia as a cathode active material for ASSLBs. However, the poor interfacial compatibility between the electrode and electrolytes has significantly hindered the development of LFP-based ASSLBs. In this study, an advanced Li2ZrCl6 (LZC) – Li9.54Si1.74P1.4S11.7Cl0.3 (LiSiPSCl) bilayer electrolyte is rationally designed for LFP-based ASSLBs, aiming to simultaneously achieve favorable interfacial compatibilities with both the LFP cathode layer and alloy anode layer. As a result, the developed LFP-LZC/LZC/LiSiPSCl/Li–In ASSLB can not only deliver a high initial discharge capacity of 144.9 mA h g−1, but also manifest a high-capacity retention up to 89% after 400 cycles at the current density of 1C. The strategy used in this work sheds light on a promising method to engineer stabilized interfaces for LFP-based ASSLBs. [ABSTRACT FROM AUTHOR]

With regard to retired LiFePO4 batteries, resource treatment has become a matter of public concern. The currently used wet recycling process causes secondary environmental pollution and has the difficulty of full-component recovery. Therefore, a green and efficient recovery process for the realization of full-component recovery of LiFePO4 black powder is proposed in this work. In this closed-loop process with liquid flow circulation, no waste liquid and gas emission is generated, and the purity of recycled Li2CO3 can reach up to 99.4%. Moreover, battery-grade FePO4 can be obtained after simple treatment, solving the problem of lithium tailings and slag in the traditional wet recycling process. The performances of recycled Li2CO3 and FePO4 are similar to commercialization products according to electrochemical tests. More importantly, the resynthesized LiFePO4 cathode displays high-capacity retention of 97.5% after 200 cycles at 0.5 C, indicating the superiority of our strategy. Furthermore, the pouch cell with 5.2 A h presents outstanding performance, and high-capacity retentions of 96% and 95.2% can be observed after 500 cycles at 0.5 C and 1 C, respectively. The aforementioned results indicate the attractive prospects of this green and efficient lithium extraction and full-component recovery process. [ABSTRACT FROM AUTHOR]

Lithium sulfide (Li2S) is the critical raw material used for the synthesis of sulfide solid-state electrolytes, but its high cost and pollution restrict the commercialization of sulfide solid-state electrolytes and sulfide-based all-solid-state batteries. A new green and cost-effective method for the synthesis of high-quality Li2S is designed and proposed in this work. The method of reducing Li2SO4 with H2 circumvents the disadvantages of many side reactions, complicated purification processes, impure products and emission of greenhouse gases (CO and CO2) associated with traditional carbothermal reduction methods, and high-purity Li2S (H-Li2S) is obtained. Subsequently, H-Li5.6PS4.6Cl1.4 solid electrolyte was synthesized and compared with the C-Li5.6PS4.6Cl1.4 electrolyte synthesized from commercial Li2S (C-Li2S). The ionic conductivity (8.06 mS cm−1) and chemical/electrochemical stability as cathode/anode material were better than those of C-Li5.6PS4.6Cl1.4. Besides, the rate performance and long cycling stability of an all-solid-state lithium battery NCM//Li5.6PS4.6Cl1.4//Li–In assembled with H-Li5.6PS4.6Cl1.4 are better than those of batteries assembled with C-Li5.6PS4.6Cl1.4. It can maintain a discharge capacity of 133.23 mA h g−1 after 300 cycles at 1C (95% of the initial discharge capacity), and has a high discharge capacity of 127.9 mA h g−1 at 3C. The high electrochemical performance of the all-solid-state battery confirms the superiority of high-purity H-Li2S and the advantages of the hydrogen reduction method. [ABSTRACT FROM AUTHOR]