Thick Electrode Design in Lithium-Ion Batteries

Thick electrodes offer a direct route to higher energy densities and reduced manufacturing costs in lithium‐ion cells by increasing the ratio of active material to inactive components. Such electrodes, typically exceeding 200 µm in thickness, can deliver greater areal capacities but face inherent challenges in charge‐ and mass‐transport kinetics. As thickness increases, ion diffusion pathways lengthen and electrolyte infiltration can become non‐uniform, leading to concentration gradients, increased polarization and diminished rate capability. Mechanical cohesion within the electrode, adhesion to the current collector and thermal management also become critical concerns. To overcome these limitations, researchers have explored tailored microstructures—graded porosity, aligned channels, low‐tortuosity scaffolds and three‐dimensional architectures—alongside advanced fabrication methods such as freeze‐casting, laser structuring and templating. These innovations aim to balance high mass loading with rapid ion and electron transport, ensuring uniform utilisation of active material during high‐power operation. By optimising pore networks, particle distribution and binder strategies, thick electrodes are positioned to meet the demanding requirements of electric vehicles, grid storage and portable electronics while supporting cost-effective, high-throughput production.

Research from Nature Portfolio

Recent studies have established unified models to elucidate rate limitations in composite electrodes of varying thicknesses. One seminal work presents an empirical equation that accurately fits capacity versus rate data across diverse chemistries, yielding characteristic timescales and linking them to diffusion coefficients, electrolyte conductivities and electrode dimensions. This framework enables identification of dominant rate-limiting processes and predicts upper speed limits for lithium‐ion cells. Complementing this, another influential investigation introduced a set of five characteristic parameters—three time constants for ion transport in electrolyte, solid diffusion in active particles and interfacial depletion, plus two resistances quantifying ionic and electronic transport within the electrode. By applying electrochemical modelling to reveal the interplay of these parameters, this work provides quantitative guidelines for designing thick electrodes with minimal performance penalties at medium to high C-rates.

Thick Electrode Design in Lithium-Ion Batteries publication trend

The graph below shows the total number of articles in thick electrode design in lithium-ion batteries across all publications each year (not limited to Nature Index journals).

Technical terms

Areal mass loading: The mass of active material per unit electrode area, expressed in mg cm⁻², determining the cell’s energy capacity at fixed footprint.

Tortuosity: A dimensionless measure of the complexity of ion transport pathways through the porous electrode, affecting diffusion resistance.

C-rate: A dimensionless rate defining charge or discharge current relative to the cell’s nominal capacity; e.g., 1C discharges in one hour.

Porosity: The fraction of void volume in the electrode structure, influencing electrolyte infiltration and ion transport.

Diffusion coefficient: A parameter quantifying the speed of ion or molecule migration within solids or liquids, often in m² s⁻¹.

References

1. Thick Electrodes for High Energy Lithium Ion Batteries. Journal of The Electrochemical Society (2015).
2. Quantifying the factors limiting rate performance in battery electrodes. Nature Communications (2019).
3. Elucidating the Performance Limitations of Lithium-ion Batteries due to Species and Charge Transport through Five Characteristic Parameters. Scientific Reports (2016).
4. Optimization of laser-patterned electrode architectures for fast charging of Li-ion batteries using simulations parameterized by machine learning. Energy Storage Materials (2023).
5. Development of a roll-to-roll high-speed laser micro processing machine for preparing through-holed anodes and cathodes of lithium-ion batteries. International Journal of Extreme Manufacturing (2023).