Date of Award
Doctor of Philosophy
Metallurgical and Materials Engineering
Juan C. Noveron
Nowadays, our society depends on fossil fuels as the main energy source. However, depletion, price fluctuations, and other concerns, such as global warming, have led to an exhaustive research for renewable energy resources. Here is where electrochemical energy systems play a critical role since they can provide power when renewable energy is not available. Among these electrochemical energy storage systems Li-ion batteries (LIBs) have shown higher volumetric, gravimetric, and power density capacities over other battery systems.
However, commercial LIBs are still relying on graphite base materials for the anode. However, graphite possesses a low specific capacity. Recently, transition metal compounds have reached great attention as anode materials due to their high theoretical capacity, i.e. 1230 mAh/g for MnO2 vs 372 mAh/g for graphite. However, transition metal-based compounds suffer from low electric conductivity and poor cycling stability. Consequently, this Dissertation primary focus was to improve cycling capabilities of the transition metal compounds investigated.
Here we present strategies to improve the electrochemical performance of transition metal compounds as anode materials for Li-ion Batteries. Particularly, CoMoS/bio-carbon composites, hollow MnO 2 spheres with a polyaniline coating, and porous iron sulfide/carbon composites were synthesized. Particularly, CoMoS/bio-carbon improved significantly with a ~60% charge capacity at the 200 th cycle vs ~10% capacity at the 100 th cycle for its control. MnO2 /PANI composite demonstrated a charge capacity of 200% at the 250 th cycle vs 5% capacity of its control. For porous iron sulfide/carbon composites, sample 2X increased 30% its capacity from cycle 3 to the 450 th , and retained ~65% its initial charge capacity vs ~12% capacity for sample 4X.
Received from ProQuest
Dominguez, Noemi, "Strategies To Improve The Electrochemical Of Performance Transition Metal Compounds As Anode Materials For Li-Ion Batteries" (2019). Open Access Theses & Dissertations. 61.