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Unraveling the reaction paths and structural evolutions during charging/discharging processes are critical for the development and tailoring of silicon anodes for high‐capacity batteries. However, a mechanistic understanding is still lacking due to the complex phase transformations between crystalline (c‐) and amorphous (a‐) phases involved in electrochemical cycles. In this study, by employing a newly developed machine learning potential, the key experimental phenomena not only reproduce, including voltage curves and structural evolution pathways, but also provide atomic scale mechanisms associated with these phenomena. The voltage plateaus of both the c‐Si and a‐Si lithiation processes are predicted with the plateau value difference close to experimental measurements, revealing the two‐phase reaction mechanism and reaction path differences. The observed voltage hysteresis between lithiation and delithiation mainly originates from the transformation between the c‐Li15‐δSi4 and a‐Li15‐δSi4 phases. Furthermore, stress accumulation is simulated along different reaction paths, indicating a better cycling stability of the a‐Si anode due to the lower stress concentration. Overall, the study provides a theoretical understanding of the thermodynamics of the complex structural evolutions in Si anodes during (de)lithiation processes, which may play a role in optimizations for battery performances. [ABSTRACT FROM AUTHOR]

In hybrid perovskites, the organic molecules and inorganic frameworks exhibit distinct static and dynamic characteristics. Their coupling will lead to fascinating phenomena, such as large polarons, dynamic Rashba–Dresselhaus effects, etc. In this paper, deep potential molecular dynamics (DPMD) is employed, a large‐scale MD simulation scheme with DFT accuracy, to study hybrid perovskites formamidinium lead iodide (FAPbI3) and methylamonium lead iodide (MAPbI3). A spontaneous hybrid nano‐domain behavior, namely multiple molecular rotation nano‐domains embedded into a single [PbI6]4− octahedra rotation domain, is first discovered at low temperatures. The behavior originates from the interplay between the long range order of molecular rotation and local lattice deformation, and clarifies the puzzling structural features of FAPbI3 at low temperatures. The work provides new insights into the structural characteristics and stability of hybrid perovskite, as well as new ideas for the structural characterization of organic–inorganic coupled systems. [ABSTRACT FROM AUTHOR]

High interfacial resistance between electrodes and solid‐state electrolyte is the major cause for the failure of all‐solid‐state Li‐ion batteries. Spontaneous (electro)chemical reactions and poor Li‐ion diffusion at the interfaces are closely related to this increased impedance. Although introducing a coating layer can mitigate interfacial reactions and structural reconstruction, it may also lead to poor Li‐ion diffusion. Balancing this trade‐off therefore is crucial for the design of coating layer materials. In this study, the impact of the amorphous LiF (a‐LiF) coating layer on interfacial structural reconstruction and Li‐ion diffusion at the LiCoO2/Li6PS5Cl solid‐state interface is explicitly elucidated via machine‐learning‐assisted molecular dynamics (MD) simulations. It is found that the a‐LiF can effectively protect the P‐S tetrahedron local structures in Li6PS5Cl but cannot suppress the formation of side product S2 dimers. It is further discovered that once the a‐LiF coating exceeds a certain critical thickness, emergence of ordered local structures will inhibit Li‐ion diffusion. The simulations propose that the optimal thickness of the coating layer is around 1 nm. Overall, the work provides a microscopic understanding for effects of the a‐LiF coating layer on the structural and kinetic properties of cathode‐solid electrolyte interfaces and can guide the design of interfacial coating materials for solid‐state batteries. [ABSTRACT FROM AUTHOR]