Improving the Performance of Lithium‐Ion Batteries Using a Two‐Layer, Hard Carbon‐Containing Silicon Anode for Use in High‐Energy Electrodes

Abstract

Lithium‐ion battery cells with high‐energy density and good fast charging properties are subject of current research. One approach to achieve high‐energy densities is the use of higher mass loadings. The challenges of these so called “thick” electrodes are transport limitations: lithium ions cannot reach all layers of the electrode, which results in a drop of performance. Possible concepts to overcome these limitations are the use of different active materials (silicon oxide, graphite, and hard carbon (HC)), and a two‐layer coating of the anode to create a defined pore network, which reduces the ionic resistance and ensure better fast charging capability even at higher mass loadings (8 mAh cm−2). It could be demonstrated that by using a two‐layered anode with HC in the upper layer, the electrical conductivity could be increased by a factor of 10 compared to the reference anode. Furthermore, the interporous HC leads to a capacity retention increase up to 20% with no loss of capacity at moderate C‐rates and a low electrode density. This can be explained by the low tortuosity that results in additional conductive paths for the ions through the coating, reduces the ionic resistance, and ultimately enables faster lithiation of the anode.

An electrode design study: laser structuring of anodes for fast-charging of batteries

“…Several ways of modifying the electrode architecture to increase fast-charging capability are contrary to current research. For instance, multilayer coating, blending of different active materials, and structuring of the electrode with laser ablation are being investigated and show an increase in fast-charging capabilities [5][6][7][8][9][10][11]. Several patterns for laser structuring, including hole, line, and grid patterns are investigated in the literature [8,10,12].…”

Influence of Electrode Structuring Techniques on the Performance of All‐Solid‐State Batteries

“…Perforated electrodes effectively reduce concentration gradients, improving ionic transport and thus enabling better cell performance at elevated currents [39] . Similarly, multilayer coatings were suggested to enhance ion transport in the porous electrodes, providing higher power density [41–44] . Transfer of these approaches to ASSBs might be a viable pathway towards improved cell performance.…”

“…[39] Similarly, multilayer coatings were suggested to enhance ion transport in the porous electrodes, providing higher power density. [41][42][43][44] Transfer of these approaches to ASSBs might be a viable pathway towards improved cell performance.…”

Numerical Investigation of Conductivity Additive Dispersion in High‐Power and High‐Energy NMC‐Based Lithium‐Ion Battery Cathodes: Application‐Based Guidelines

“…Kremer et al [ 16 ] were able to show that low drying rates could improve the rate capability of high‐energy thick electrodes. Gottschalk et al [ 17 ] reported the improvement in the performance of LIB anodes by means of a two‐layered microstructure.…”