2D Porous Nanostructured Materials for Energy Storage and Sensing Applications

Nanotechnologies : Physical Science Apps

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Inventors

  • Guihua Yu, Ph.D. , Mechanical Engineering
  • Pan Xiong , University of Texas at Austin
  • Lele Peng , University of Texas at Austin

Background/unmet need

Lithium-ion batteries (LIB) have emerged as the energy storage devices of choice for many applications because of their unique characteristics in energy and power density. Still, there is a continued demand for higher storage capacity and cyclability. One of the focus areas of development is the anode design, where improvements in Li+ storage capacity and stability over current graphite design can lead to much higher energy density and longer, more stable battery life.

Of the many material schemes, transition metal oxides (TMOs), including simple TMOs with one type of transition metal element and mixed TMOs (MTMOs) with multiple elements, are a family of functional materials showing great potential in not only LIB anode designs, but also catalysis and sensing applications. Up till now, TMO nanomaterials are mainly obtained in the form of zero-dimensional (0D) nanoparticles, 1D nanotubes or nanowires, and 3D nanoclusters or microspheres. However, 2D nanostructures, especially those free-standing nanosheets with confined thickness and large surface area would be most suitable for a LIB anode design. Yet such TMO materials have remained absent due to challenges in suitable synthesis methods and material characteristics. Thus a new scalable synthesis method is highly desired.

Invention Description

A group in the Department of Mechanical Engineering at The University of Texas at Austin, led by Dr. Guihua Yu, has developed an innovative approach for the synthesis of 2D porous TMO nanostructures with controllable pore size. The method can be applied to a vast range of different materials: transition metal oxides, lithium metal oxides, metal phosphates, metal chalcogenides, and others. Tunable pore size can be realized by adjusting initial concentration ratio or calcination temperatures.

Initial LIB anode testing of a porous ZnMn2O4 nanosheet shows high specific capacity and very good cycling stability. In one experiment, after an initial discharge capacity of 525 mAh/g, the 2D holey sheet achieved capacity retentions of 97.7%, 95.4%, and 89.3% at the end of 100, 200 and 500 cycles, respectively, and stabilized at 86.2% throughout prolonged cycling of over 1,000 cycles--representing the best performance for long-cycle LIBs with TMO-based anodes thus far.

Benefits/Advantages

  • Much higher surface area in a free-standing, flexible, and 2D porous nanosheet with controllable pore size
  • Manufacturing method is facile, scalable, and cost effective.
  • Demonstrated superior performance in specific capacity, rate capability, and long cycling stability in a LIB anode design

Market potential/applications

Energy storage and conversion devices used in personal electronics, automotive and residential applications; sensor devices used for gas/chemical detection

Development Stage

Lab/bench prototype