Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


Dissertation Kewei Liu.pdf (9.76 MB)

ETD Abstract Container

Abstract Header

FABRICATION OF STRUCTURED POLYMER AND NANOMATERIALS FOR ADVANCED ENERGY STORAGE AND CONVERSION

Liu, Kewei
http://rave.ohiolink.edu/etdc/view?acc_num=akron1542022285390711

Abstract Details

2018, Doctor of Philosophy, University of Akron, Polymer Science.
Since the first and second industrial revolutions, the development of energy conversion and storage technologies have brought great progress and convenience to modern society. Most of the innovations and technologies focus on the carbon-based fuels such as coal, petroleum and natural gas, which are not only limited resources and but also harmful for the environment. Meanwhile, the power demand from industries and societies has been growing rapidly in the recent years. In this consideration, a number of research efforts have been intensively applied to pursue alternative clean energy resources and new energy storage and conversion systems, such as supercapacitors, lithium-ion batteries, metal-oxygen, water electrolysis and so on. In this dissertation, we report the synthesis and preparation of a series of polymer and nanomaterials with controllable composition and structure, to fit for the specific requirement in different systems and promote the device performance. In order to prevent the aggregation of graphene sheets, we designed a method to fabricate 3D macro porous graphene by using bi-continuous polymer templates. The structure and pore size of the graphene can be controlled by corresponding polymer templates. The resulting graphene monolith materials were used as the supercapacitor electrode and exhibited excellent stability (over 6000 cycles with capacity retention of 98%). This work provides a novel way to fabricate high-quality, macroporous graphene that can be useful in applications such as electrochemical energy storage electrodes and high surface area catalyst scaffolds. To investigate the Li-oxygen battery discharge reaction pathway, patterned Au-nanodots as surface-enhanced Raman substrates are prepared by using a universal method of metal deposition through a nano-shadow mask. The discharge products on different electrodes (graphene and gold) were analyzed and the results indicated that the reaction process on the lithium-air cathode was significantly dependent upon the change of cathode materials. To develop a stable, efficient, non-noble metal-based electrocatalysts for oxygen evolution reaction, we have synthesized hollow and conductive iron-cobalt phosphide (Fe-Co-P) alloy nanostructures using a Fe-Co metal organic complex as a precursor. The Fe-Co-P alloy exhibits excellent OER activity with a specific current density of 10 mA/cm2 being achieved at an overpotential of 252 mV. Our results conclude that the electrochemical-induced high-valent iron stabilizes the cobalt in a low-valent state, leading to the simultaneous enhancement of activity and stability of the OER catalyst. For the purpose of developing high energy storage lithium ion batteries, we have synthesized highly porous Mn3O4/C nanospheres with the hierarchical structure as anode materials by self-assembly to form a spherical Mn-based metal organic complex, followed by a facile thermal annealing process. The Mn3O4/C nanospheres consisted of homogeneously distributed Mn3O4 nanocrystals with a conformal carbon coating. Such a hierarchical, porous structure provided both good electrical conductivity and volume changes accommodation capability. In order to mitigate the dendrite formation on the Li-metal electrode, 2D Ni3 (2,3,6,7,10,11-hexaiminotriphenylene) 2 (Ni3 (HITP) 2) metal-organic framework was also explored as the nano-host for Li deposition. During cycling, the high intrinsic electrical conductivity of Ni3 (HITP) 2 evens potential difference on the Li metal surface and the nano-channel structure enables fast Li-ion and organic molecules through 2D nanosheets and endows nano hosts for Li nucleation and deposition. The 2D conductive MOF modified Li electrode exhibits an excellent coulombic efficiency of 99.95% in the Li/ Li2 Ti5 O12 (LTO) cell for 500 cycles. In order to improve the safety of lithium-ion batteries, we have explored a high yield method to prepare surface-modified glass fiber pillars strengthened shear thickening electrolyte from the conventional Li-ion battery electrolyte. The volume fraction of the fillers could be lowered compared with the spherical fillers due to the high aspect ratio of the glass fiber pillars. The electrochemical stability of this impact resistant electrolyte was further evaluated in the half-cell and full-cell characterizations. Ballistic tests were also carried out to monitor the voltage variation with different impact energies. In this thesis, we have introduced a number of synthesis and preparation methods to fabricate structured polymer and nanomaterials. These materials are employed as electrodes, electrolyte fillers and catalyst by adjusting the composition, structure, and surface of the materials. The fabrication and evaluation of the energy storage and conversion devices (supercapacitors, Li-ion, Li-oxygen batteries, and alkaline water electrolysis) are also included.
Yu Zhu (Advisor)
Toshikazu Miyoshi (Committee Chair)
Mesfin Tsige (Committee Member)
Steven Chuang (Committee Member)
Bryan Vogt (Committee Member)
216 p.
Materials Science; Polymer Chemistry; Polymers
Polymer blend, Nanomaterials, Li-ion batteries, Supercapacitors, Li-oxygen battery

Recommended Citations

Citations

  • Liu, K. (2018). FABRICATION OF STRUCTURED POLYMER AND NANOMATERIALS FOR ADVANCED ENERGY STORAGE AND CONVERSION [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1542022285390711

    APA Style (7th edition)

  • Liu, Kewei. FABRICATION OF STRUCTURED POLYMER AND NANOMATERIALS FOR ADVANCED ENERGY STORAGE AND CONVERSION . 2018. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1542022285390711.

    MLA Style (8th edition)

  • Liu, Kewei. "FABRICATION OF STRUCTURED POLYMER AND NANOMATERIALS FOR ADVANCED ENERGY STORAGE AND CONVERSION ." Doctoral dissertation, University of Akron, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1542022285390711

    Chicago Manual of Style (17th edition)

akron1542022285390711
73
© 2018, all rights reserved.
This open access ETD is published by University of Akron and OhioLINK.