Understanding and Mitigating Mechanical Degradation in Li-S Batteries

Research Overview

Resnick Fellow Max Saccone and Professor Julia Greer have recently developed a new additive manufacturing technique for lithium sulfide (Li₂S) composites for use as battery cathodes. The three dimensionally architected composites were also studied for their mechanical properties, which could improve lithium-sulfur battery lifetimes, allowing these batteries to compete economically against lithium-ion technology for both transportation and stationary storage applications. The results are published in their new paper, "Understanding and mitigating mechanical degradation in Li-S batteries: additive manufacturing of Li₂S composites and nanomechanical particle compressions."

Scientific Achievement

We report a novel additive manufacturing technique for air-sensitive Li-S cathode materials, and measure mechanical deformation of Li₂S particles.

Image Lightbox

Download Full Image

Significance and impact

• Li-S batteries use earth-abundant materials, with great potential for grid storage applications
• This work aims to solve significant challenges with mechanical degradation and capacity fade

Technical Details

• A water-in-oil emulsion enables additive manufacturing of air-sensitive composites.
• The technique provides a 3x improved resolution over prior additively manufactured Li-S materials.
• Li₂S particle compression experiments reveal conditions for material cracking, which can inform better electrode design.

Nanomechanical compression-to-failure experiments on Li2S. (a) Load vs. displacement data for a representative particle compression that contains a typical initial elastic loading region, yield point, post-elastic deformation associated with deviation from the Hertzian contact model, crack initiation, and ultimate failure. (b) Contact pressure vs. displacement with the same regions denoted in (a).

Image Lightbox

Nanomechanical compression-to-failure experiments on Li2S. (a) Load vs. displacement data for a representative particle compression that contains a typical initial elastic loading region, yield point, post-elastic deformation associated with deviation from the Hertzian contact model, crack initiation, and ultimate failure. (b) Contact pressure vs. displacement with the same regions denoted in (a).

Download Full Image

Electrochemical characterization of Li2S–C composite. (a) The first five cycles of cyclic voltammograms of an architected Li2S–C cathode vs. Li metal, at a scan rate of 10 µV/s. (b) Discharge profiles of an architected Li2S–C cathode vs. Li at C/20 rate for the 1st, 10th, 50th, and 100th cycles. (c) Capacity and Coulombic efficiency vs. cycle number for architected Li2S–C cathodes, with error bars representing the standard error of the mean for two replicate cells. (d) Capacity of architected Li2S–C vs. other architected cathodes for Li–S batteries as a function of minimum critical dimensions.

Image Lightbox

Electrochemical characterization of Li2S–C composite. (a) The first five cycles of cyclic voltammograms of an architected Li2S–C cathode vs. Li metal, at a scan rate of 10 µV/s. (b) Discharge profiles of an architected Li2S–C cathode vs. Li at C/20 rate for the 1st, 10th, 50th, and 100th cycles. (c) Capacity and Coulombic efficiency vs. cycle number for architected Li2S–C cathodes, with error bars representing the standard error of the mean for two replicate cells. (d) Capacity of architected Li2S–C vs. other architected cathodes for Li–S batteries as a function of minimum critical dimensions.

Download Full Image

Saccone, M. A. & Greer, J. R., Understanding and mitigating mechanical degradation in Li-S batteries: additive manufacturing of Li₂S composites and nanomechanical particle compressions, J. Mater. Res. 1–11 (2021). doi:10.1557/s43578-021-00182-w.

Contact: Julia Greer