Yao Group research has been primarily focused on the design and synthesis of materials and architectures to address new challenges arising in the applications of energy storage and conversion. What distinguishes our research from others is the deep and novel understanding of distinct challenges in each application we studied, driven by an integrated theoretical and experimental approach rooted on first-principles-based multiscale modeling through collaboration and state-of-the-art multimodal operando characterizations. Due to the unique combination of research background in organic materials and inorganic nanomaterials, our group has studied a broad range of materials including two-dimensional materials, inorganic nanostructures, organic crystals, polymers, and organic/inorganic hybrid materials. Yao Group was officially founded in September 2012.

Direction 1: Multivalent Ion Intercalation Materials for High Energy Batteries
Multivalent metals like magnesium and aluminum are very-low-cost elements and can deliver ultra-high volumetric energy density in batteries, but the high polarization strength of the corresponding cations induces strong electronic interaction between cations and the intercalation framework, leading to intrinsic difficulty for these cations to intercalate into common intercalation host materials. PI proposed an innovative approach to alleviate such strong interaction. The proposed research integrates the PI’s expertise in nanostructure-engineering, combined with electrochemical, computational, and microscopic approaches, to demonstrate high performance rechargeable magnesium batteries. This research paves the way towards efficient multivalent cation-intercalation materials as well as ultra-high energy rechargeable batteries.

Representative Publications:
Hyun Deog Yoo, Yanliang Liang, Hui Dong, Junhao Lin, Hua Wang, Yisheng Liu, Lu Ma, Tianpin Wu, Yifei Li, Qiang Ru, Yan Jing, Qinyou An, Wu Zhou, Jinghua Guo, Jun Lu, Sokrates T. Pantelides, Xiaofeng Qian & Yan Yao*, Nature Communications 2017, 8, 339.

Yifei Li, Qinyou An, Yingwen Chen, Yanliang Liang, Yang Ren, Cheng-Jun Sun, Hui Dong, Zhongjia Tang, Guosheng Li*, Yan Yao*, Nano Energy 2017, 34, 188-194.

Y.Liang, H.D.Yoo, Y.Li, J.Shuai, H.A.Calderon, F.C.R.Hernandez, L.C.Grabow, and Y.Yao* Nano Lett. 2015, 15, 2194-2202. [PDF]

H.D.Yoo,Y.Liang, Y.Li, and Y.Yao* ACS Appl. Mater. Interfaces 2015, 7, 7001-7007. [PDF]

Direction 2: Advanced Aqueous Lithium-Ion Batteries
We will develop a battery using a novel water-based, lithium-ion chemistry that makes use of sustainable, low-cost, high-energy, organic materials. Combining the ‘rocking-chair’ principle of conventional RLBs and the use of low-cost, nonflammable aqueous electrolyte, aqueous rechargeable lithium batteries (ARLBs) offer a significant advantage over organic electrolyte based RLBs in terms of safety and many other aspects such as flexibility in vehicle design and system cost reduction. The aim of this proposed project is to use a group of completely innovative electrochemical redox couples that leverage “matured” rechargeable lithium battery cathode chemistry characteristics and develop a reliable and high capacity anode material. UH’s new batteries will meet today’s performance standards, while minimizing the potential impact of battery failure, thus offering manufacturers greater flexibility with regard to vehicle design.

Representative Publications:

Yanliang Liang, Yan Jing, Saman Gheytani, Kuan-Yi Lee, Ping Liu, Antonio Facchetti*, Yan Yao*, Nature Materials 2017, 16, 841.

Saman Gheytani, Yanliang Liang, Feilong Wu, Yan Jing, Hui Dong, Karun K. Rao, Xiaowei Chi, Fang Fang*, Yan Yao*, Advanced Science 2017, 1700465 [PDF]

Yanliang Liang, Zhihua Chen, Yan Jing, Yaoguang Rong, Antonio Facchetti*, and Yan Yao*, J. Am. Chem. Soc. 2015, 137, 4956-4959. [PDF]

Saman Gheytani, Yanlaing Liang, Yan Jing, Jeff Xu, and Yan Yao*, Journal of Materials Chemistry A 2015, 4, 395-399. [PDF]

Direction 3: All-solid-state Na batteries
All-solid-state sodium batteries (ASSSB) will be developed that will operate near room temperature, exhibit higher energy densities than all other Na batteries, function over a many-year lifetime, and be scalable in manufacturing, extremely safe, and based entirely upon recyclable and renewable materials. These batteries will be very low cost and sustainable in the ~10^6 metric ton quantities needed for grid-scale applications. A novel renewable-carbon-sourced high-energy-density and low-voltage (near unit activity for Na) anode will be combined with a new high Na+ ion solid electrolyte. These will be paired with a novel low-cost, high-voltage, and energy-dense renewable-carbon-sourced cathode. This transformative and disruptive Na battery technology conceptualizes and redesigns Na batteries away from current problematic liquid batteries that are high temperature, corrosive, reactive, low energy density, and dangerous. Instead, these new ASSSB are based upon a benign and scalable solid-stack design that operates reversibly, near room temperature, and at high energy densities.

Representative Publications:
Xiaowei Chi, Yanliang Liang, Fang Hao, Ye Zhang, Justin Whiteley, Hui Dong, Pu Hu, Sehee Lee, Yan Yao*, Angewandte Chemie Int. Ed. 2018, in press.

Direction 4: Critical Control of Intermediate Phase Transformation for Efficient Perovskite Solar Cells:
The overall goal of this project is to create uniform and high-quality perovskite films to enhance the efficiency of planar-heterojunction perovskite solar cells. The objective is to identify the crystal structure and composition of the intermediate phases and further probe the kinetics of phase transition to desirable perovskite phase. The detailed tasks are (a) to understand the crystal structure and chemical composition of intermediate phase; (b) to in-situ probe the temperature-dependent intermediate phase transition of mixed halide based perovskite; and (c) to investigate charge transport by time-resolved optoelectronic spectroscopy of perovskite solar cells. This information will aid in understanding the precursor-solvent interaction and intermediate phase-perovskite transformation, and enable the optimization of processing conditions for complete conversion of intermediate phase to final phase perovskite films.

Representative Publications:
Swaminathan Venkatesan, Fang Hao, Junyoung Kim, Yaoguang Rong, Zhuan Zhu, Yanliang Liang, Jiming Bao and Yan Yao*, Nano Research 2017, 10, 1413-1422.

Yaoguang Rong, Zhongjia Tang, Yufeng Zhao, Xin Zhong, Swaminathan Venkatesan, Harrison Graham, Matthew Patton, Yan Jing, Arnold M. Guloy* and Yan Yao*, Nanoscale 2015, 7, 10595-10599. [PDF]

Yaoguang Rong, Swaminathan Venkatesan, Rui Guo, Yanan Wang, Jiming Bao, Wenzhi Li, Zhiyong Fan, Yan Yao*, Nanoscale 2016, DOI: 10.1039/C6NR00488A. [PDF]