UC San Diego

Lithium-ion batteries are one of the most promising energy storage devices for their light weight and superior cycling stability. However, the state-of-the-art lithium-ion batteries cannot satisfy the ever-increasing market demand of high energy density electrochemical energy devices. Advanced lithium batteries based on novel electrode materials could provide higher energy density thus become a hot research topic.This dissertation will discuss the designs and applications of novel electrode materials to address the performance challenges for different types of energy storage devices. Chapter 2 provides a new strategy to fabricate a “lithium-free” all-solid-state battery. The 3D hybrid anode design improves the cycling stability of all-solid-state batteries by overcoming the commonly observed cell failure due to the electrode volume change and lithium dendrite growth. This design provides a promising approach towards a high energy density, long life, and low-cost all-solid-state battery technology. In Chapter 3, a concentrated ether-based electrolyte with LiTFSI and LiNO3 as co-salts is proposed, which enables stable cycling of a Li-SPAN battery. In addition to providing excellent protection for lithium metal anodes by forming the solid electrolyte interface (SEI), the electrolyte promotes the formation of a crystalline cathode electrolyte interface (CEI) on the SPAN surface composed of LiF and LiNO2. The CEI effectively prevents the formation of soluble polysulfide species and enables stable cycling of the Li-SPAN batteries. In Chapter 4, a V2O5-Si multi-layer composite anode is proposed and fabricated. The mixed conductive V2O5 layer effectively confines the volume change of Si layer and prevents the parasitic reactions between Si and electrolyte. This strategy enables the anode a long cycle life as well as a long calendar life while maintaining high energy density.