Prof. Dr. Xin He

Lithium (Li) metal with high theoretical capacity and low electrochemical potential is the most ideal anode for next-generation high-energy batteries. However, the practical implementation of Li anode has been hindered by dendritic growth and volume expansion during cycling, which results in low Coulombic efficiency (CE), short lifespan, and safety hazards. Here, we report a highly stable and dendrite-free Li metal anode by utilizing N-doped hollow porous bowl-like hard carbon/reduced graphene nanosheets (CB@rGO) hybrids as three-dimensional (3D) conductive and lithiophilic scaffold host. The lithiophilic carbon bowl (CB) mainly works as excellent guides during the Li plating process, whereas the rGO layer with high conductivity and mechanical stability maintains the integrity of the composite by confining the volume change in long-range order during cycling. Moreover, the local current density can be reduced due to the 3D conductive framework. Therefore, CB@rGO presents a low lithium metal nucleation overpotential of 18 mV, high CE of 98%, and stable cycling without obvious voltage fluctuation for over 600 cycles at a current density of 1 mA·cm⁻². Our study not only provides a good CB@rGO host and pre-Lithiated CB@rGO composite anode electrode, but also brings a new strategy of designing 3D electrodes for those active materials suffering from severe volume expansion.

14 December 2018 in Nature Communications

Journal Article

Fluorine-free water-in-ionomer electrolytes for sustainable lithium-ion batteries

Bo Yan

Zigeng Liu

+10

The continuously increasing number and size of lithium-based batteries developed for large-scale applications raise serious environmental concerns. Herein, we address the issues related to electrolyte toxicity and safety by proposing a “water-in-ionomer” type of electrolyte which replaces organic solvents by water and expensive and toxic fluorinated lithium salts by a non-fluorinated, inexpensive and non-toxic superabsorbing ionomer, lithium polyacrylate. Interestingly, the electrochemical stability window of this electrolyte is extended greatly, even for high water contents. Particularly, the gel with 50 wt% ionomer exhibits an electrochemical stability window of 2.6 V vs. platinum and a conductivity of 6.5 mS cm⁻¹ at 20 °C. Structural investigations suggest that the electrolytes locally self-organize and most likely switch local structures with the change of water content, leading to a 50% gel with good conductivity and elastic properties. A LiTi₂(PO₄)₃/LiMn₂O₄ lithium-ion cell incorporating this electrolyte provided an average discharge voltage > 1.5 V and a specific energy of 77 Wh kg⁻¹, while for an alternative cell chemistry, i.e., TiO₂/LiMn₂O₄, a further enhanced average output voltage of 2.1 V and an initial specific energy of 124.2 Wh kg⁻¹ are achieved.

2 September 2024 in Nature Nanotechnology

Journal Article

Revealing the degradation pathways of layered Li-rich oxide cathodes

Zhimeng Liu

Yuqiang Zeng

Junyang Tan

Hailong Wang

Yudong Zhu

Xin He

+14

About Me

Prof. Dr. Xin He is a distinguished researcher and doctoral supervisor at the School of Chemical Engineering, Sichuan University, and a selected candidate of the “Double Hundred Talent Program” of Sichuan University. He holds a Bachelor of Engineering degree in Polymer Materials and Engineering from the School of Materials Science and Engineering at East China University of Science and Technology, a Master of Materials Science and Engineering degree from the School of Materials Science and Engineering at Saarland University in Germany and Luleå University in Sweden, and a PhD from the Department of Physical Chemistry at the University of Münster in Germany and the MEET Battery Research Center. He was a postdoctoral researcher at the Helmholtz Institute in Germany and the Lawrence Berkeley National Laboratory in the United States. His main research directions are the design, preparation, and testing of advanced energy storage materials; the development and application of dynamic sensors; the research and development of new battery detection and monitoring technologies; and the modular design and integration of battery management systems. His research results have been published in more than 40 authoritative journals such as Nature, Advanced Energy Materials, and Chemistry of Materials, among which he is the first author (including co-first author) and corresponding author of 15 papers. He has been granted 4 international patents and 1 U.S. patent.

Prof. Dr. Xin He

Prof. Dr. Xin He

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