An Innovative Process for Ultra‐Thick Electrodes Elaboration: Toward Low‐Cost and High‐Energy Batteries

Abstract

An effective route to enhance the volume ratio of active materials in a lithium‐ion battery (LIB) or sodium‐ion battery (NaB) consists in increasing the electrode thickness, that is, active mass loading, as it reduces the volume and weight fractions of the separator and current collectors in the cell. This approach also serves to reduce the battery cost, chiefly associated with the expensive polymeric separator. However, following the standard industrial coating process, the mechanically stable electrode can hardly exceed an active mass loading of about 30 mg cm−2, corresponding to a nominal areal capacity around 6 mAh cm−2 due to the binder migration during the drying step. Herein, a straightforward manufacturing process based on a filtration technique is developed. It enables the design of LIB electrodes with a nominal areal capacity up to 20 mAh cm−2. A pierced and serrated current collector allows at the same time both filtration and mechanical interlocking of the electrode layer. Cells assembled with such ultra‐thick filtered electrodes exhibit very promising performances, thereby promoting the design of high‐energy and low‐cost LIBs and NaBs by a fast fabrication process.

From Fundamental Understanding to Engineering Design of High‐Performance Thick Electrodes for Scalable Energy‐Storage Systems

“…Because increasing research attention has been paid to thick electrode design, an overview of the research statistics in this field is essential to benchmark the current research status. Here, we summarize the information on the abovementioned electrode design parameters as well as energy/power density indicators from 62 publications related to thick electrodes, [ 8,9,12–15,20,21,24,39,40,43–45,50,62–104 ] (Table S2, Supporting Information) and the results of the statistical analysis are discussed in the following section.…”

“…We include all the studies that provided sufficient data for us to conduct a consistent half‐cell analysis. [ 9,14,21,24,40,44,45,62,64,70,71,74–76,81,88,105,106 ] Studies that only carried out fixed‐rate cycling for thick electrodes while using relatively thin electrodes for rate capacities are not included here since power density favors thin electrodes and it would not be a fair comparison.…”

Performance and ageing behavior of water-processed LiNi0.5Mn0.3Co0.2O2/Graphite lithium-ion cells

“…In fact, as electrochemical processes are dependent on the temperature contrary to electronic phenomena, impedance measurements at 0°C and 25°C have been carried out to confirm that the semi-circle described by the resistance R2 corresponds to the resistance of surface film for the graphite anode, and contact resistance for the NMC cathode. The high frequency loop is rather assigned to the electronic resistance of the electrodes (particle-toparticle and particle-to-collector) 10,30,33,34 . This semicircle is modeled by a resistance R2 in parallel with a constant phase element Q2.…”

Synergetic effect of aqueous electrolyte and ultra‐thick millimeter‐scale LiFePO 4 cathode in aqueous lithium‐ion batteries

“…Porcher et al and Yu et al have described special preparative procedures involving porous, 3D current collection, and laser patterning to produce electrodes with a thickness of several hundred micrometers with having electrolyte channels and high conductivity. 14,17 However, the corresponding capacity exhibited in commercial C-rate tests is significantly lower than the theoretical value and results in a loss of energy density. Moreover, the large overpotential induces the growth of lithium dendrites at the surface of the negative electrode and the non-uniform degradation of active materials.…”