Visualizing Lithium Deposition and Identifying Two Types of Dendrites in Extreme-Fast-Charging Full Cells across the Entire Lifespan by EPR and EPR Imaging.

Metallic lithium deposition processes in NCM811∥graphite full cells during extreme-fast charging of 4 C (fully charged within 15 min) are detected via electron paramagnetic resonance (EPR) and EPR imaging over hundreds of cycles to quantify lithium deposits and visualize their spatial distribution. EPR imaging shows that constant-voltage charge generates loose Li dendrites with divergent growth whereas overcharge leads to long dendrites with vertical growth, and these Li deposits accumulate at the anode edges, which could deplete the Li resource at the cathode edges. Moreover, quantitative EPR indicates that the stripping current correlates to the deposit surface areas, while the reintercalation current depends on the contact areas between plated Li and graphite.

All-Solid-State Batteries with Pre-plated Ultrathin Lithium Metal Enabled by No Pressure Holding and Characterized by Electron Paramagnetic Resonance Imaging.

All-solid-state batteries with ultrathin lithium metal, close to the anode-free solid-state batteries, could achieve high energy density. However, it is not trivial to plate an ultrathin lithium metal layer on a Cu current collector (Cu-CC). electron paramagnetic resonance (EPR) imaging showed that the pre-plating on Cu-CC in a Li-In|LiPSCl|Cu cell without pressure holding produced a lithium metal layer with a small area.