Rechargeable batteries have become indispensable implements in our daily life and are considered a promising technology to construct sustainable energy systems in the future. The liquid electrolyte is one of the most important parts of a battery and is extremely critical in stabilizing the electrode-electrolyte interfaces and constructing safe and long-life-span batteries. Tremendous efforts have been devoted to developing new electrolyte solvents, salts, additives, and recipes, where molecular dynamics (MD) simulations play an increasingly important role in exploring electrolyte structures, physicochemical properties such as ionic conductivity, and interfacial reaction mechanisms. This review affords an overview of applying MD simulations in the study of liquid electrolytes for rechargeable batteries. First, the fundamentals and recent theoretical progress in three-class MD simulations are summarized, including classical, ab initio, and machine-learning MD simulations (section 2). Next, the application of MD simulations to the exploration of liquid electrolytes, including probing bulk and interfacial structures (section 3), deriving macroscopic properties such as ionic conductivity and dielectric constant of electrolytes (section 4), and revealing the electrode-electrolyte interfacial reaction mechanisms (section 5), are sequentially presented. Finally, a general conclusion and an insightful perspective on current challenges and future directions in applying MD simulations to liquid electrolytes are provided. Machine-learning technologies are highlighted to figure out these challenging issues facing MD simulations and electrolyte research and promote the rational design of advanced electrolytes for next-generation rechargeable batteries.

Applying Classical, Ab Initio, and Machine-Learning Molecular Dynamics Simulations to the Liquid Electrolyte for Rechargeable Batteries.

Efficient electrode materials, that combine high power and high energy, are the crucial requisites of sodium‐ion batteries (SIBs), which have unwrapped new possibilities in the areas of grid‐scale energy storage. Hard carbons (HCs) are considered as the leading candidate anode materials for SIBs, however, the primary challenge of slow charge‐transfer kinetics at the low potential region (<0.1 V) remains unresolved till date, and the underlying structure–performance correlation is under debate. Herein, ultrafast sodium storage in the whole‐voltage‐region (0.01–2 V), with the Na+ diffusion coefficient enhanced by 2 orders of magnitude (≈10–7 cm2 s–1) through rationally deploying the physical parameters of HCs using a ZnO‐assisted bulk etching strategy is reported. It is unveiled that the Na+ adsorption energy (Ea) and diffusion barrier (Eb) are in a positive and negative linear relationship with the carbon p‐band center, respectively, and balance of Ea and Eb is critical in enhancing the charge‐storage kinetics. The charge‐storage mechanism in HCs is evidenced through comprehensive in(ex) situ techniques. The as prepared HCs microspheres deliver a record high rate performance of 107 mAh g–1 @ 50 A g–1 and unprecedented electrochemical performance at extremely low temperature (426 mAh g–1 @ −40 °C).

Enabling Fast Na+ Transfer Kinetics in the Whole‐Voltage‐Region of Hard‐Carbon Anodes for Ultrahigh‐Rate Sodium Storage

Improved high-temperature cyclability of AlF3 modified spinel LiNi0.5Mn1.5O4 cathode for lithium-ion batteries

Metal-organic framework-mediated synthesis of LiNi0.5Mn1.5O4: Tuning the Mn3+ content and electrochemical performance by organic ligands

Boosted electrochemical performance of LiNi0.5Mn1.5O4 via synergistic modification of Li+-Conductive Li2ZrO3 coating layer and superficial Zr-doping

Self-optimizing weak solvation effects achieving faster low-temperature charge transfer kinetics for high-voltage Na3V2(PO4)2F3 cathode

Suppressed phase separation in spinel LiNi0.5Mn1.5O4 cathode via interstitial sites modulation

Revealing the Thermodynamics and Kinetics of In-Plane Disordered Li2MnO3 Structure in Li-Rich Cathodes

LiNi0.5Mn1.5O4(LNMO) material has high theoretical capacity and high operating voltage. Nonetheless, LNMO has still many problems which include oxidative decomposition of electrolyte at high voltage and dissolution of transition metals into electrolyte. In this work, oxides of both La and Al (LAO) were coated on the surface LNMO by a wet chemical method. LAO is estimated to improve cycling performance (both room and elevated temperatures) and rate capability of LNMO due to the synergistic effect of La2O3 and Al2O3. Al2O3 can protect LNMO from the corrosion of HF that derives from decomposition of LiPF6, which results in mitigating the solution of Mn2+. Al2O3 can also prompt electrochemical reversibility of LNMO. La2O3 can enhance electrical conductivity, availing to charge transfer. Furthermore, La2O3 presents splendid thermal stability, which may boost the interfacial stability of LNMO. La2O3 can also alleviate the formation of the passive layer. The effect of coating content on performances of LNMO was also studied in detail. The capacity retention of 94.0% for the optimal coating LNMO with 4.0 wt.% (mLa2O3/mAl2O3 = 3: 1) is shown at 1 C and 25 °C after 200 cycles, and its capacity retention of 95.0% is exhibited at 1 C and 55 °C after 100 cycles. Its remarkable discharge capacities at 10, 15, and 20 C are 107.4, 94.4, and 82.7 mAh g−1, respectively, and its capacity retention of 93.3% is displayed at 5 C at room temperature after 500 cycles.

Yi Han

Papers

Self-optimizing weak solvation effects achieving faster low-temperature charge transfer kinetics for high-voltage Na3V2(PO4)2F3 cathode

Boosted electrochemical performance of LiNi0.5Mn1.5O4 via synergistic modification of Li+-Conductive Li2ZrO3 coating layer and superficial Zr-doping

Suppressed phase separation in spinel LiNi0.5Mn1.5O4 cathode via interstitial sites modulation

Revealing the Thermodynamics and Kinetics of In-Plane Disordered Li2MnO3 Structure in Li-Rich Cathodes

Design of synergistic-coated layer of La 2 O 3 /Al 2 O 3 in LiNi 0.5 Mn 1.5 O 4 cathode for enhanced cycling stability and rate capability