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LiPF 6 as a dominant lithium salt of electrolyte is widely used in commercial rechargeable lithium-ion batteries due to its well-balanced properties, including high solubility in organic solvents, good electrochemical stability, and high ionic conductivity. However, it suffers from several undesirable properties, such as high moisture sensitivity, thermal instability, and high cost. To address these issues, herein, we propose an electron-donation modulation (EDM) rule for the development of low-cost, sustainable, and electrochemically compatible LiNO 3 -based electrolytes. We employ high donor-number solvents (HDNSs) with strong electron-donation ability to dissolve LiNO 3 , while low donor-number solvents (LDNSs) with weak electron-donation ability are used to regulate the solvation structure to stabilize the electrolytes. As an example, we design the LiNO 3 -DMSO@PC electrolyte, where DMSO acts as an HDNS and PC serves as an LDNS. This electrolyte exhibits excellent electrochemical compatibility with graphite anodes, as well as the LiFePO 4 and LiCoO 2 cathodes, leading to stable cycling over 200 cycles. Through spectroscopy analyses and theoretical calculation, we uncover the underlying mechanism responsible for the stabilization of these electrolytes. Our findings provide valuable insights into the preparation of LiNO 3 -based electrolytes using the EDM rule, opening new avenues for the development of advanced electrolytes with versatile functions for sustainable rechargeable batteries., (© 2024 Wiley-VCH GmbH.)

Low-temperature performance of lithium-ion batteries (LIBs) has always posed a significant challenge, limiting their wide application in cold environments. In this work, the high-performance LIBs working under ultralow-temperature conditions, which is achieved by employing the weak-solvation and low-viscosity isobutyronitrile as a cosolvent to tame the affinity between solvents and lithium ions, is reported. The as-prepared electrolytes exhibit a sufficiently high conductivity (1.152 mS cm -1 ) at -70 °C. The electrolytes enable LiCoO 2 cathode and graphite anode to achieve high Coulombic efficiency of >99.9% during long-term cycling at room temperature, and to respectively achieve 75.8% and 100.0% of their room-temperature capacities at -40 °C. Even the LiCoO 2 //graphite pouch cells can retain 68.7% of the room-temperature capacity when discharged at -70 °C, and present stable cycling performance at -40 and 60 °C. This work provides a solution for the development of advanced electrolytes to enable LIBs working at wide-temperatures range., (© 2023 Wiley-VCH GmbH.)

The solvation structure of Li + plays a significant role in determining the physicochemical properties of electrolytes. However, to date, there is still no clear definition of the solvating power of different electrolyte solvents, and even the solvents that preferentially participate in the solvation structure remain controversial. In this study, we comprehensively discuss the solvating power and solvation process of Li + ions using both experimental characterizations and theoretical calculations. Our findings reveal that the solvating power is dependent on the strength of the Li + -solvent (ion-dipole) interaction. Additionally, we uncover that the anions tend to enter the solvation sheath in most electrolyte systems through Li + -anion (ion-ion) interaction, which is weakened by the shielding effect of solvents. The competition between the Li + -solvent and Li + -anion interactions ultimately determines the final solvation structures. This insight into the fundamental understanding of the solvation structure of Li + provides inspiration for the design of multifunctional mixed-solvent electrolytes for advanced batteries., (© 2023 Wiley-VCH GmbH.)

The anionic redox reaction (ARR) has attracted extensive attention due to its potential to enhance the reversible capacity of cathode materials in Li/Na-ion batteries (LIBs/SIBs). However, the understanding of its activation mechanism is still limited by the insufficient mastering of the underlying thermodynamics and kinetics. Herein, a series of Mg/Li/Zn-substituted Na x MnO 2 and Li x MnO 2 cathode materials are designed to investigate their ARR behaviors. It is found that the ARR can be activated in only Li-substituted Li x MnO 2 and not for Mg- and Zn-substituted ones, while all Mg/Li/Zn-substituted Na x MnO 2 cathode materials exhibit ARR activities. Combining theoretical calculations with experimental results, such a huge difference between Li and Na cathodes is closely related to the migration of substitution ions from the transition metal layer to the alkali metal layer in a kinetic aspect, which generates unique Li(Na)-O-□ TM and/or □ Li/ Na -O-□ TM configurations and reducing reaction activation energy to trigger the ARR. Based on these findings, an ion-migration mechanism is proposed to explain the different ARR behaviors between the Na x MnO 2 and Li x MnO 2 , which can not only reveal the origin of ARR in the kinetic aspect, but also provide a new insight for the development of high-capacity metal oxide cathode materials for LIBs/SIBs., (© 2022 Wiley-VCH GmbH.)