Document Type

Dissertation - Open Access

Award Date

2023

Degree Name

Doctor of Philosophy (PhD)

Department / School

Electrical Engineering and Computer Science

First Advisor

Xiaojun Xian

Abstract

Large-scale energy storage devices play a key role in regulating the renewable energy to build a carbon-free sustainable future, but the widely used lithium-ion batteries cannot meet the demands because of the limited lithium resource and high cost. Thus, it is urgent to develop next-generation battery technologies with low cost and high safety. Sodium-ion battery is considered as a promising candidate due to the abundant sodium resources and low cost. Its practical application, however, is hindered by the absence of the advanced electrode materials. The tin-based anodes deliver high theoretical capacities and show great promise for the sodium-ion batteries, but the large volume expansion upon cycling can damage the structure and lead to short cycling life. In this dissertation, three tin-base anodes have been developed. First, a free-standing Sn@CFC electrode was synthesized via the electrospinning method. The carbon fiber and Sn nanoparticles together provide fast ions and electrons pathway, enabling a dominant pseudocapacitance contribution. Moreover, the facile manufacturing technique yields the Sn@CFC electrode with a high mass loading. Second, a novel anode was designed with a pomegranate-like structure that the SnP2O7 nanoparticles dispersed in the robust N-doped carbon matrix. The carbon matrix forms strong interaction with the SnP2O7 nanoparticles, leading to a stable structure without any particle aggregation. Third, a SnS/Sb2S3 heterostructure was prepared and encapsulated in the sulfur and nitrogen co-doped carbon matrix with engineered porous structure. The porous structure can provide void space to alleviate the volume expansion upon cycling, guaranteeing excellent structural stability. The unique heterostructure and the S, N co-doped carbon matrix together facilitate fast-charge transport to improve reaction kinetics. Aqueous zinc-ion batteries show great promise in large-scale energy storage. However, the decomposition of water molecules leads to severe side reactions, resulting in the limited lifespan of the zinc-ion batteries. Here, the tetrahydrofuran additive was introduced into the zinc sulfate electrolyte to reduce the water activity by modulating the solvation structure of the Zn hydration layer. Thus, in an optimal 2 M ZnSO4/THF (5% by volume) electrolyte, the hydrogen evolution reaction and byproduct precipitation can be suppressed, which greatly improves the cycling stability and Coulombic efficiency.

Library of Congress Subject Headings

Energy storage.
Storage batteries.
Electrodes.
Electrolytes.
Renewable energy sources.

Number of Pages

163

Publisher

South Dakota State University

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Rights Statement

In Copyright