Proximity Matters: Interfacial Solvation Dictates Solid Electrolyte Interphase Composition

Delineating the Impact of Diluent on High-Concentration Electrolytes for Developing High-Voltage LiNi0.5Mn1.5O4 Spinel Cathode

LiNi0.5Mn1.5O4 (LNMO) is a high-voltage spinel cathode with low nickel content, making it an attractive candidate for next-generation lithium-ion batteries (LIBs). However, its application is limited by interfacial instability with conventional carbonate-based electrolytes at high voltages. In this work, a localized saturated electrolyte (LSE) capable of stably operating up to 4.85 V is investigated. Molecular dynamics simulations and Fourier transform infrared spectroscopy reveal that adding "non-solvating" 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether diluent in the saturated electrolyte, more PF6 - anions are present in the first solvation shell of Li+, at the expense of solvent molecules. This tailored solvation environment promotes the formation of a robust, LiF-rich cathode-electrolyte interphase that mitigates transition metal dissolution and parasitic side reactions. The optimized LSE enables excellent cycling performance, with 95% capacity retention in Li|LNMO half-cells after 100 cycles and 94% retention in Li4Ti5O12|LNMO full cells after 250 cycles, even at a practically relevant LNMO cathode loading of ≈15 mg cm-2. These results highlight the benefits of electrolyte engineering and solvation structure control in advancing high-voltage LIB technologies.

Breaking Aggregation State to Achieve Low-Temperature Fast Charging of Lithium Metal Batteries

Insufficient ionic conductivity and elevated desolvation energy barrier of electrolytes limit the low-temperature applications of lithium metal batteries (LMBs). Weakly solvating electrolytes (WSEs), with limited lithium salt dissociation capability, are prone to desolvate and drive anion-rich aggregates (AGGs). However, significant AGGs result in increased viscosity and low ionic mobility, contributing to battery failure at low temperatures (≤-20 °C). Here, we propose and achieve a transformation of WSEs' solvation structures from AGGs to contact ion pairs (CIPs) through modulating the overall solvation capability, thereby achieving the balance between weak Li+- solvent interactions and desired ion migration kinetics. Remarkably, CIPs-dominated electrolyte shows a ten-fold increase in ionic conductivity compared to conventional WSEs. The Li||LiFePO4 (LFP) battery achieves more than 1400 cycles with 86.9 % capacity retention at 5 C. The practical 1.2 Ah LFP pouch cell delivered 69 % of the capacity at 25 °C when cycled at -40 °C. This strategy for solvation structure transformation in WSEs provides a novel approach for the development of electrolytes for low-temperature batteries.

Perovskite-Type CaVO3 Nanocomposite as High-Performance Anode Material for Lithium-Ion Batteries

Electric vehicles' rapid development has put higher requirements on the performance of lithium-ion batteries (LIBs). However, the specific capacity of a commercial graphite anode (372 mAh g-1) has become the bottleneck for further improvement. Therefore, it is urgent to develop novel anode materials with superior performance. Herein, we propose crystalline-amorphous dual-phase CaVO3 nanocomposites as LIB anodes. Benefiting from the stable perovskite structure and high conductivity of CaVO3, the nanocomposite follows the intercalation mechanism, resulting in no capacity decay during 5000 cycles. In addition, due to the multielectron transfer provided by amorphous high-valent vanadium oxide, the nanocomposite can provide a high specific capacity of 442.8 mAh g-1 with a suitable average working potential of 0.95 V. The ingenious strategy of constructing nanocomposites through spontaneous oxidation of nanoparticles is expected to be extended to the perovskite oxide family, inspiring the development of more high-performance LIB anodes.

Advances in performance degradation mechanism and safety assessment of LiFePO4for energy storage

In the context of 'energy shortage', developing a novel energy-based power system is essential for advancing the current power system towards low-carbon solutions. As the usage duration of lithium-ion batteries for energy storage increases, the nonlinear changes in their aging process pose challenges to accurately assess their performance. This paper focuses on the study LiFeO4(LFP), used for energy storage, and explores their performance degradation mechanisms. Furthermore, it introduces common battery models and data structures and algorithms, which used for predicting the correlation between electrode materials and physical parameters, applying to state of health assessment and thermal warning. This paper also discusses the establishment of digital management system. Compared to conventional battery networks, dynamically reconfigurable battery networks can realize real-time monitoring of lithium-ion batteries, and reduce the probability of fault occurrence to an acceptably low level.

Robust Ionics Reinforced Fiber As Implantable Sensor for Early Operando Monitoring Cell Thermal Safety of Commercial Lithium-Ion Batteries

Commercial batteries have been largely applied in mobile electronics, electric vehicles, and scalable energy storage systems. However, thermal runaway of batteries still obstructs the reliability of electric equipment. Considering this, building upon recent investigations of energy thermal safety, commercially available organogel fiber-based implantable sensors have been developed through 3D printing technology for first operando implantable monitoring of cell temperature. The printed fibers present excellent reliability and superelasticity because of internal supramolecular cross-linking. High temperature sensitivity (-39.84% °C-1/-1.557% °C-1) within a wide range (-15 to 80 °C) is achieved, and the corresponding mechanism is clarified based on in situ temperature-dependent Raman technology. Furthermore, taking the pouch cell as an example, combined with finite element analysis, the real-time observation system of cell temperature is successfully demonstrated through an implanted sensor with wireless Bluetooth transmission. This enlightening approach paves the way for achieving safety monitoring and smart warnings for various electric equipment.