Li-ion batteries (LIBs) have been the leading technology in the portable electronics market since their discovery by Sony in the 1990s. At the anode, graphite has remained ubiquitous for commercial Li-ion batteries since its discovery as a reversible intercalation material over 30 years ago, leading to a typical specific energy density of ca. 150 Wh/kg. However, due to both rising consumer demand for enhanced capabilities of portable electronics and the emerging application of Li-ion batteries to larger systems (such as electric vehicles and even grid-scale energy storage), it has become clear that existing cell components will not be sufficient. Therefore, it is important to develop new active materials and electrolytes that allow Li-ion battery energy and power density to be doubled in the near future.

One of the most promising classes of anode materials are conversion transition metal oxides (MOs). These MOs rely on chemical transformations with more than one electron transfer step to store and deliver energy, which results in theoretical capacities 2-3 times higher than graphite. In addition, they have a safer lithiation potential that eliminates the possibility for problematic lithium plating during charging. Lastly, MOs are naturally abundant and typically environmentally friendly. However, the use of metal oxides in their raw state has been limited by their low electronic conductivity – which promotes phase separation and large domain sizes from the metal and Li2O phases that form during charging. It is this nanoscale phenomena that limits MO cycle life to graphite compared to graphite [1]. To circumvent these challenges, our group has focused on methods that increase the intra-particle and inter-particle electronic conductivity of the anode electrode [2-4]. In this talk, we will discuss the efficacy of several approaches to improve conductivity and capacity retention in NiO, Co3O4 and MnO chemistries, including supporting the MOs onto advanced carbons, creating metal-metal oxide composites and transition metal doping. There will be a specific focus on material families that have been engineered, through fundamental scientific discoveries, to achieve stable anode electrodes over several hundred cycles. We will also discuss opportunities and challenges when pairing these MO anode materials with traditional cathodes in full cells.

References.

1. N. Spinner, L. Zhang, W. Mustain, Journal of Materials Chemistry A, 2 (2014) 16278.
2. N. Spinner, A. Palmieri, N. Beauregard, L. Zhang, J. Campanella and W. E. Mustain, Journal of Power Sources, 276 (2015) 46.
3. Y. Liu, A. Palmieri, J. He, Y. Meng, N. Beauregard, S.L. Suib and W.E. Mustain, Scientific Reports, 6 (2016) 25860.
4. A. Palmieri, R. Kashfi-Sadabad, S. Yazdani, M. Pettes, W. E. Mustain, Electrochimica Acta, 213 (2016) 620.