Silicon Based Anodes

Silicon alloys have the highest specific capacity when used as anode material for lithium-ion batteries, however, the drastic volume change inherent in their use causes formidable challenges toward achieving stable cycling performance. Large quantities of binders and conductive additives are typically necessary to maintain good cell performance.

Projects

High Energy Density Silicon Monoxide Anode

We report only 2% (by weight) functional conductive polymer binders without any conductive additives was successfully used with a micron-size silicon monoxide (SiOx) anode material, demonstrating stable and high gravimetric capacity (> 1000 mAh/g) for ~500 cycles and more than 90% capacity retention.

**Reference**: Hui Zhao, Zhihui Wang, Peng Lu, Meng Jiang, Feifei Shi, Xiangyun Song, Ziyan Zheng, Xin Zhou, Yanbao Fu, Guierfi Abdelbast, Xinecheng Xiao, Zhi Lin, Vincent Battaglia, Karim Zaghib, and Gao Liu, Toward practical application of functional conductive polymer binders for a high-energy lithium-ion battery design. Nano Letters, 2014. 14(11), 6704-6710.

Full cell built with the SiOx anode and LFP cathode shows remarkable stable capacity and impedance.

Graph showing SiOx anode and LPF cathode using Gen 2 electrolyte and 5% FEC as an additive — SiOx anode and LPF cathode using Gen 2 electrolyte and 5% FEC as an additive

Graph showing impedance of the SiOx-LFP full cell at 50% of SOC. — Impedance of the SiOx-LFP full cell at 50% of SOC.

High Energy Density Si Anode with In Situ Formed Network Structure

Si micron size particles can be used with Si nanoparticles as conductive additive and connection pathways to from stable 3D Si electrode.

Schematic of lithiation and delithiation process of composite anode electrodes — Schematics of lithiation and delithiation process of composite anode electrodes using micron-sized Si particles as active lithium-ion storage materials. (a) When an acetylene black conductive additive is used, the absolute volume expansion of any individual particles is in cube micrometer range. This large volume change has pushed the binders and AB composite to expand during charge. During discharge, the AB/binder composite does not fully recover, leaving gaps between the Si active materials and the AB/binder conductive matrix. (b) When Si nanoparticles are used as an additive along with a conductive polymer binder during the charge process, the Si nanoparticles and micron-sized Si tend to fuse to form a network structure to cushion the volume expansion. The physical connections between the micron-sized Si particles and the conductive network are preserved during the discharge process.

Electrochemical performance of composite electrodes (a) m-Si/AB/PFM, (b) m-Si/n-Si/PFM

Reference

Wu, M. Y.; Sabisch, J. E. C.; Song, X. Y.; Minor, A. M.; Battaglia, V. S.; Liu, G., In Situ Formed Si Nanoparticle Network with Micron-Sized Si Particles for Lithium-Ion Battery Anodes. Nano Letters 2013, 13 (11), 5397-5402.

Featured Publications

Zhu, Tianyu, and Gao Liu."Communication—Functional Conductive Polymer Binder for Practical Si-Based Electrodes."Journal of The Electrochemical Society 168.5 (2021) 050533. DOI

Zhao, Hui, Zhihui Wang, Peng Lu, Meng Jiang, Feifei Shi, Xiangyun Song, Ziyang Zheng, Xin Zhou, Yanbao Fu, Guerfi Abdelbast, Xingcheng Xiao, Zhi Liu, Vincent S Battaglia, Karim Zaghib, and Gao Liu."Toward practical application of functional conductive polymer binder for a high-energy lithium-ion battery design."Nano Letters 14 (2014) 6704–6710. DOI

Xun, Shidi, Bin Xiang, Andrew M Minor, Vincent S Battaglia, and Gao Liu."Conductive Polymer and Silicon Composite Secondary Particles for a High Area-Loading Negative Electrode."Journal of The Electrochemical Society 160.9 (2013) A1380-A1383. DOI

Wu, Mingyan, Julian E. C Sabisch, Xiangyun Song, Andrew M Minor, Vincent S Battaglia, and Gao Liu."In Situ Formed Si Nanoparticle Network with Micron-Sized Si Particles for Lithium-Ion Battery Anodes."Nano Letters 13 (2013) 5397-5402. DOI