Li growth and SEI engineering for anode free Li metal rechargeable batteries: A review of current advances

Li metal battery systems are attractive for next generation high energy batteries due to their high theoretical specific capacity and Li metal's low redox potential. Anode free Li metal batteries (AFLBs) have a higher energy density than conventional Li metal batteries because the anode material is absent in the pristine state. An additional advantage is that the battery production costs are relatively low due to simplified anode coating processing, which makes AFLBs favorable for large scale industrial production. Despite these advantages, commercializing AFLBs remains challenging because of the high reactivity of Li metal and dendrite growth issues at the anode side. The chemical and physical properties of solid electrolyte interphase (SEI) formed at Li metal anodes determine the Li ion transport kinetics, Li metal deposition behavior, and overall cycling performance. The key to resolving these issues is to grow a homogeneous Li metal and design a stable SEI. Many approaches, such as electrolyte optimization and artificial layers design, have been developed to guide a uniform Li metal growth and form a stable SEI, facilitating rapid Li ion transport and suppressing Li dendrite growth and other undesirable side reactions. An overview of these discoveries and developments in Li growth and SEI en gineering and insights into the intrinsic mechanisms of battery performance, presented in this review, is, therefore, of great interest to the battery research community

Influence of the SEI Formation on the Stability and Lithium Diffusion in Si Electrodes

Silicon (Si) is an attractive anode material for Li-ion batteries (LIBs) due to its high theoretical specific capacity. However, the solid-electrolyte interphase (SEI) formation, caused by liquid electrolyte decomposition, often befalls Si electrodes. The SEI layer is less Li-ion conductive, which would significantly inhibit Li-ion transport and delay the reaction kinetics. Understanding the interaction between the SEI components and Li-ion diffusion is crucial for further improving the cycling performance of Si. Herein, different liquid electrolytes are applied to investigate the induced SEI components, structures, and their role in Li-ion transport. It is found that Si electrodes exhibit higher discharge capacities in LiClO4-based electrolytes than in LiPF6-based electrolytes. This behavior suggests that a denser and more conductive SEI layer is formed in LiClO4-based electrolytes. In addition, a coating of a Li3PO4 artificial SEI layer on Si suppresses the formation of natural SEI formation, leading to higher capacity retentions. Furthermore, galvanostatic intermittent titration technique (GITT) measurements are applied to calculate Li-ion diffusion coefficients, which are found in the range of 10-23-10-19 m2/s

Overcoming polar‐format issues in synthetic aperture radar multichannel autofocus

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/166214/1/rsn2bf00419.pd