Interfacial factors affecting the performance of oxide-free silicon for lithium-ion batteries revealed by correlative electrochemical microscopy

Session

Nanoscale Science of Materials for Energy Storage and Generation

Authors

Xiangdong Xu (1), Dr. Daniel Martín-Yerga (1, 6), Dr. Nicholas Grant (4), Dr. Geoff West (5), Sophie Pain (4), Dr. Minkyung Kang (3), Dr. Marc Walker (2), Prof. John Murphy (4), Prof. Patrick Unwin (1, 6)

Affiliations

1. Department of Chemistry, University of Warwick
2. Department of Physics, University of Warwick
3. Institute for Frontier Materials, Deakin University
4. School of Engineering, University of Warwick
5. Warwick Manufacturing Group, University of Warwick
6. The Faraday Institution, Quad One, Harwell Campus

Keywords

Silicon, Li-ion battery, solid electrolyte interphase, scanning probe microscopy

Abstract text

Silicon is regarded as one of the most promising materials for negative electrodes in high energy density lithium-ion batteries (LiBs). Understanding the solid electrolyte interphase (SEI) formation and lithiation/delithiation kinetics is important to improve the electrochemical performance of silicon-based LiBs. However, these processes are still unclear and, especially, the role of the silicon surface termination is a matter of debate. Here, we used scanning electrochemical cell microscopy (SECCM) to compare the local electrochemical behaviour of native oxide silicon (SiO_x/Si) and hydrofluoric acid etched silicon (HF-Si) as models of negative LiB electrodes. SiO_x/Si and HF-Si showed different electrochemical behaviour in terms of lithiation potential, kinetics and delithiation reversibility. SECCM was complemented with correlative secondary ion mass spectroscopy (SIMS) to visualise the SEI composition and distribution and rationalise the effect of the surface silicon oxide. Correlative SECCM/SIMS is demonstrated as a powerful approach to understand complex structure-function relationships and battery interfaces at the nano- and microscales.

References