Lithium-ion batteries (LiB) offer a low-cost, long cycle-life and high energy density solution to the automotive industry. There is a growing need of fast charging batteries for commercial application. However, under certain conditions of high currents and/or low temperatures, the chance for Li plating increases. If the anode surface potential falls below 0 V vs Li/Li+, the formation of metallic Li is thermodynamically feasible. Therefore, determination of accurate Li plating curve is crucial in estimating the boundary conditions for battery operation without compromising life and safety. There are various electrochemical and analytical methods that are employed in deducing the Li plating boundary of the Li-ion batteries. The present paper reviews the common test methods and analysis that are currently utilized in Li plating determination. Knowledge gaps are identified, and recommendations are made for the future development in the determination and verification of Li plating curve in terms of modeling and analysis.

Electrolytes play a critical role in enabling the stable cycling of rechargeable lithium (Li) metal batteries. While carbonate-based and ether-based electrolytes are widely investigated with notably improved electrochemical performances in Li metal batteries, few works have been conducted for systematical understanding and comparison of these two systems. Here, we side-by-side investigated carbonate-based (dimethyl carbonate, DMC) and ether-based (1,2-dimethoxyethane, DME) electrolyte systems in terms of cathodic chemical/electrochemical stabilities, anodic stability, transport properties, Li morphology, Coulombic efficiency, and full cell performances. The experimental results indicate that ether-based electrolyte systems exhibit all-around superior compatibilities with Li metal anode, although the carbonate-based systems can be significantly improved from the commercial baseline by introducing fluorinated co-solvent. The ether-based systems, even at low concentrations, demonstrate acceptable anodic stability when charged to a reasonable cut-off voltage in practical applications. This work sheds light on advanced electrolyte development toward practical Li metal batteries.

Lithium-ion batteries (LiB) offer a low-cost, long cycle-life, and high energy density solution to the automotive industry. There is a growing need of fast charging batteries for commercial applications. However, under certain conditions such as high currents and/or low temperatures, the chance for Lithium (Li) plating increases. The main reason behind plating is the slow solid-state diffusion of Li ions inside the active material. If the anode surface potential falls below 0 V versus Li/Li+, the formation of metallic Li is thermodynamically feasible. Therefore, the determination of an accurate Li plating curve is crucial in estimating the boundary conditions for battery operation without compromising life and safety. There are various electrochemical and analytical methods that are employed in evaluating the Li plating boundary of an LiB. The present paper reviews the common test methods and analysis methods that are currently utilized in Li plating determination. An overview of existing methods, their advantages and limitations are provided in detail.

Lithium-ion batteries provide a low-cost, long cycle-life and high energy density solution to the expediting energy requirement of the automotive industry. There is a growing need of fast charging batteries for commercial application. However, large charging currents may cause Lithium plating which describes the deposition of metallic Lithium at the anode surface. It takes place at conditions of high currents and/or low temperatures because of kinetic limitations. The main reason behind plating is the slow solid-state diffusion of Lithium ions inside the active material. If the anode surface potential falls below 0 V versus Li/Li+, the formation of metallic Lithium is thermodynamically feasible. To avoid or reduce the amount Lithium plating, it is essential to detect its onset during a charging event. Determination of accurate Lithium plating curve is crucial in estimating the boundary conditions for battery operation without compromising life and safety. There are various data analysis methods involved in deriving the Lithium plating curve: anode potential using a three-electrode cell, variation of relaxation voltage after charging (dV/dt), variation of accumulated charge with voltage (dQ/dV) and coulombic efficiency of charge/discharge with %SOC (state of charge) are more commonly employed techniques. In addition to these methods, estimation of its occurrence is typically underpinned by electrochemical models where the negative (anode) electrode potential is expressed by a set of partial differential equations based on the electrochemical and physical properties of the battery components such as the electrodes and electrolyte. The present paper reviews the common test methods and analysis that are currently utilized in Lithium plating determination. Knowledge gaps are identified, and recommendations are made for the future development in the determination and verification of Lithium plating curve in terms of modelling and analysis.

Lithium-ion batteries (LIB) are rapidly taking over the electric vehicle (EV) industry as the main energy storage system. They provide high energy efficiency, good high-temperature performance, and low self-discharge. LIB is generally made up of a lithium metal oxide or phosphate cathode, a graphite anode, a polymer separator and a liquid electrolyte solution. The electrolyte is comprised of a lithium salt dissolved in a mixture of carbonates, such as ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), etc. The melting point of ethylene carbonate (EC, 39°C) is higher than that of its analogue propylene carbonate (PC, –48 °C) and the latter also offers higher solubility of Li salt. Therefore, PC is an attractive candidate to improve the low temperature charge/discharge capacity and the fast charge capability. Several groups have attempted to replace EC by PC. However, co-intercalation of PC-solvated Li+ results in serious exfoliation of graphite layers and a faster degradation of battery cycle life. We used a combination of additives in PC based liquid electrolyte containing LiPF6 salt, to address this issue. The developed electrolyte offers superior cycle life for the NMC/graphite pouch cell. The rationale for improved performance was analyzed with the help of characterization techniques such as electrochemical impedance spectroscopy (EIS), high precision coulometry (HPC), NMR and gas analysis.