Accurate Determination of Coulombic Efficiency for Lithium Metal Anodes and Lithium Metal Batteries

Abstract

prevent further reactions between the electrolyte and Li metal which decrease the CE, as well as Li metal dendrite growth at the Li surface. Attempts to tackle one or both of these issues have relied on approaches such as tailoring the electrolyte to modify the SEI, [6] introducing an artificial SEI or surface layer on Li metal, [7] and homogenizing the flux of Li + ions during the deposition process. [8] In the pursuit of a high performance LMB, the accurate measurement of Li CE is the most critical factor to predict the cycle life. As shown in Table 1, when the CE is close to 100%, even a 0.1% increase in CE can lead to a dramatic increase in the cycle life of Li metal batteries. However, the measurement of Li CE is often affected by various factors and the measurement methods reported in literature often give different values, even for the same cell design. For example, an extreme caution needs to be taken when handling Li samples during preparation, transfer, and analysis to avoid atmospheric exposure. With so much effort being put into making the Li metal anode a reality, there is an urgent need for a common method for the accurate determination of CE for LMAs and LMBs. Here, we investigated various factors that affect the measurement of Li CE and proposed a more accurate method to determine the CE of Li metal. In this work, we were able to develop a reliable method for measuring CE which can be used as a standardized technique by other researchers and help avoid discrepancy in reported values of CE by different groups. Very accurate values of CE can be calculated and used to quantify the amount of Li consumed during cycling and estimate the cycle life of LMBs.

Antifreezing Hydrogel with High Zinc Reversibility for Flexible and Durable Aqueous Batteries by Cooperative Hydrated Cations

“…Such insulating layer formed on the surface of the Zn foil increases the resistance, resulting in the increased µ mtc . [49] The conditioning introduces unstripped residuals on the Pt foils, which could precisely dictate the interfacial reactivity for the metal deposition. Thus, the low µ mtc is stable throughout the cycling test.…”

An ion redistributor for dendrite-free lithium metal anodes

“…Coulombic efficiency (CE) measures the amount of irreversible Li metal consumptions during repeated cycles due to the formations of SEI films and dead Li, which will directly affect the cycle life of a practical battery ( 40 ). During cycling, a fixed amount of Li ions migrates through the separator and plates on a Cu substrate, and then the deposited Li is stripped away.…”

Nitriding‐Interface‐Regulated Lithium Plating Enables Flame‐Retardant Electrolytes for High‐Voltage Lithium Metal Batteries

“…MOPEs (16 mV) shows a smaller growth overpotential than OPEs (75 mV), demonstrating a feasible growth process. The method proposed by Zhang et al . was used to determine the average CE of lithium electrodeposition (Figure f).…”