No abstract

Li‐ion batteries that can simultaneously achieve high‐energy density and fast charging are essential for electric vehicles. Graphite anodes enable a high‐energy density, but suffer from an inhomogeneous reaction current and irreversible Li plating during fast charging. In contrast, hard carbon exhibits superior rate performance but lower energy density owing to its lower initial coulombic efficiency and higher average voltage. In this work, these tradeoffs are overcome by fabricating hybrid anodes with uniform mixtures of graphite and hard carbon, using industrially‐relevant multi‐layer pouch cells (>1 Ah) and electrode loadings (3 mAh cm−2). By controlling the graphite/hard carbon ratio, this study shows that battery performance can be systematically tuned to achieve both high‐energy density and efficient fast charging. Pouch cells with optimized hybrid anodes retain 87% and 82% of their initial specific energy after 500 cycles of 4C and 6C fast‐charge cycling, respectively. This is significantly higher than the 61% and 48% specific energy retention with graphite anodes under the same conditions. The enhanced performance is attributed to improved homogeneity of the reaction current throughout the hybrid anode, which is supported by continuum‐scale modeling. This process is directly compatible with existing roll‐to‐roll battery manufacturing, representing a scalable pathway to fast charging.

Operando video microscopy on calendared graphite electrodes presents the dynamic evolution of Li plating and re-intercalation during fast charging.

Solid-state batteries (SSBs) show promise for improving energy density, cycle life, and safety. However, when active material particles are mixed with a solid electrolyte phase, the rate capability of the resulting composite electrode is often limited. As a consequence, tradeoffs between energy and power density arise, especially in thick electrodes. Herein, we fabricate graphite/Li 6 PS 5 Cl composite electrodes with varying active material fraction and thickness as model systems to probe the mechanisms that limit rate capability in composite SSB electrodes. Using operando optical microscopy, spatial variations in the local state-of-charge of graphite that arise as a result of current focusing are directly observed. Pairing these results with simulations, we identify the electrode properties that limit rate performance, including the electrostatic potential drop within the tortuous solid electrolyte phase and solid-state diffusion within the graphite domains. The results highlight the critical role of microstructure in designing composite SSB cathodes and anodes.

In this prospective paper, we first review the existing simulation tools to simulate microgalvanic corrosion during free immersion. Then, we describe a recently developed application that employs PRISMS-PF, an open-source, high-performance phase-field modeling framework. The model employed in the application accounts for the electrochemical reaction at the metal/electrolyte interface and ionic migration in the electrolyte to determine the evolution of the corrosion front. We present the implementation details for the application and discuss its features such as super-linear parallel scaling performance for a sufficiently large system. Finally, we demonstrate the capability of the application by simulating corrosion of the matrix phase of an alloy near a secondary phase particle in two and three dimensions. Graphical abstract