Strain in Nanomembrane-based Battery Anodes
Final Report Abstract
The overarching aim of this project is to initiate and advance a systematic study on the strain related performances of lithium ion batteries (LIBs). We want to design a series of experiments and to fabricate novel proof-of-principal devices, in order to understand the strain-related bottleneck in developing high performance LIBs. By doing this, we are interested in answering an important question: Is silicon, one of the most abundant materials on earth, an excellent choice for making LIB anodes? After an extensive study in the funding period, we believe that a number of challenges in developing a high energy density, excellent rate capability, long lifetime and safe LIB have been addressed. We anticipate that these research results will not be only interesting for the community working on LIBs, but also will stimulate discussions and experiments in a broader community working on nanomembranes based devices. In the project, there were four consecutive experiments. Our research strategy is to find a suitable strain buffer layer, in order to restrain the huge volume changes and the formation of unstable solid electrolyte interphase layer during the lithiation and delithiation of Si. Therefore, we have chosen TiOx in the project. Our first experiment showed that Ti3+ self-doping can significantly improve the electronic and ion conductivity of TiO2. After understanding and optimizing the TiOx strain buffer layer, we have fabricated an amorphous Si@ TiOx nanomembranes using physical vapour deposition combined with strain-released rolled-up technology. The TiO2/Si/TiO2 NMs anodes was then paired with commercial LiNi1/3Co1/3Mn1/3O2 (NCM) cathodes, and the resulting full batteries exhibit excellent lithium storage performances in terms of good cycling stability, excellent rate capability and high energy density (525 Wh kg^-1). To explore the potential of Si-based nanomembranes, we have also demonstrated a sodium ion battery based on strain-released amorphous Si nanomembranes, with its performances overwhelm that of the existing Si-based counterparts. This result will help to end the debate on whether Si is a promising anode material for sodium ion batteries. Finally, we fabricated successfully a single microtube based lithium ion battery, after solving a number of technological challenges. Thus, several exciting experiments become possible with this in-situ electrochemical platform, which will help us the gain more information on the strain-related bottleneck in Si-based energy storage devices. To investigate the strain-related performances of the single rolled-up microtubes, we planned two insitu spectroscopy experiments, namely, the micro-Raman mapping or multi-beam optical stress sensing (MOSS). Due to the limited manpower, we focused on developing the first technique, which has been used successfully in characterizing the single microtube lithium ion batteries. However, we want to emphasize that the MOSS technique is still interesting in our future studies. The outcomes from this project are quite promising. We have shown that strain buffered Si nanomembranes is a promising anode material. The Si-based full battery meets the high energy density requirement (> 500 Wh/kg) for electric vehicle and grid energy storage applications. In addition, the successful design strategy can be extended to other materials that also undergo large volume change and strain-related capacity losses.
Publications
- Introducing rolled-up nanotechnology for advanced energy storage devices. Advanced Energy Materials 6, 1600797 (2016)
J. Deng, L. Zhang, et al.
(See online at https://doi.org/10.1002/aenm.201600797) - Advances on Microsized On-chip Lithium-Ion Batteries. Small 1707847 (2017)
L. Liu, L. Zhang, et al.
(See online at https://doi.org/10.1002/smll.201701847) - Reinforcing Germanium Electrode with Polymer Matrix Decoration for Long Cycle Life Rechargeable Lithium Ion Batteries. ACS Applied Materials and Interfaces 9, 38556 (2017)
X. Sun, L. Zhang, et al.
(See online at https://doi.org/10.1021/acsami.7b12228) - Tunable pseudocapacitance in 3D TiOx nanomembranes enabling superior lithium storage. ACS Nano 11, 821 (2017)
S. Huang, L. Zhang, et al.
(See online at https://doi.org/10.1021/acsnano.6b07274) - Efficient Sodium Storage in Amorphous Si Nanomembranes for High-performance Sodium Ion Battery. Advanced Materials 30, 1706637 (2018)
S. Z. Huang, L. Zhang, et al.
(See online at https://doi.org/10.1002/adma.201706637) - Rational Engineered Amorphous TiOx/Si/TiOx Nanomembrane as an Anode Material for High Energy Lithium Ion Battery. Energy Storage Materials 12, 23 (2018)
S. Huang, L. Zhang, et al.
(See online at https://doi.org/10.1016/j.ensm.2017.11.010)
