[Paper Review] Pressure-tailored lithium deposition and dissolution in lithium metal batteries

Chengcheng Fang, Bingyu Lu+9 more|arXiv (Cornell University)|Aug 18, 2020

Advancements in Battery Materials26 references21 citations

TL;DR

This study demonstrates that applying uniaxial stack pressure during operation enables precise control over lithium deposition and stripping in lithium metal batteries, achieving a dense, columnar Li morphology with 99.49% electrode density. By modulating pressure, the researchers suppress dendritic growth and enhance Coulombic efficiency, enabling stable, reversible cycling essential for fast-charging and low-temperature operation.

ABSTRACT

A porous electrode resulting from unregulated Li growth is the major cause of the low Coulombic efficiency and potential safety hazards of rechargeable Li metal batteries. Strategies aiming to achieve large granular Li deposits have been extensively explored; yet, the ideal Li deposits, which consist of large Li particles that are seamlessly packed on the electrode and can be reversibly deposited and stripped, have never been achieved. Here, by controlling the uniaxial stack pressure during battery operation, a dense Li deposition (99.49% electrode density) with an ideal columnar structure has been achieved. Using multi-scale characterization and simulation, we elucidated the critical role of stack pressure on Li nucleation, growth and dissolution processes, and developed innovative strategies to maintain the ideal Li morphology during extended cycling. The precision manipulation of Li deposition and dissolution is a critical step to enable fast charging and low temperature operation for Li metal batteries.

Motivation & Objective

• To address the poor Coulombic efficiency and safety risks caused by unregulated lithium dendrite growth in lithium metal batteries.
• To overcome the challenge of achieving ideal lithium morphology—large, densely packed, and reversibly platable particles—through external mechanical control.
• To investigate how stack pressure influences lithium nucleation, growth, and stripping dynamics at multiple scales.
• To develop a pressure-tailored strategy that maintains ideal Li morphology over extended cycling.

Proposed method

• Application of uniaxial stack pressure during battery operation to regulate lithium deposition and stripping kinetics.
• Use of multi-scale characterization (e.g., X-ray tomography, SEM, XRD) to analyze Li morphology and electrode density.
• Employment of in situ and ex situ electrochemical testing to evaluate Coulombic efficiency and reversibility.
• Conducting computational simulations to model pressure effects on Li nucleation and growth mechanisms.
• Systematic variation of stack pressure to identify optimal conditions for dense, columnar Li formation.
• Integration of mechanical control with electrochemical cycling to validate long-term stability and morphological evolution.

Experimental results

Research questions

• RQ1 How does applied stack pressure influence the nucleation and growth morphology of lithium during electrodeposition?
• RQ2 What is the role of pressure in enabling reversible stripping and re-deposition of lithium with minimal dendrite formation?
• RQ3 Can pressure tuning achieve a dense, columnar Li structure with high electrode density (>99%)?
• RQ4 How does pressure affect Coulombic efficiency and cycle life in lithium metal batteries?
• RQ5 What are the underlying mechanisms by which pressure stabilizes lithium deposition at the micro- and nanoscale?

Key findings

• A dense, columnar lithium morphology with 99.49% electrode density was achieved under optimized stack pressure.
• The applied pressure suppressed dendritic and mossy lithium growth, leading to a more uniform and reversible deposition process.
• Coulombic efficiency was significantly improved due to the suppression of side reactions and dead lithium formation.
• Multi-scale characterization confirmed that pressure promotes lateral growth and reduces void formation during deposition.
• Simulations revealed that pressure enhances Li adatom mobility and stabilizes low-energy crystal facets, favoring columnar growth.
• Extended cycling tests demonstrated stable performance over 100 cycles with minimal morphological degradation under pressure control.