Insight into the Critical Role of Exchange Current Density on Electrodeposition Behavior of Lithium Metal

Abstract

Due to an ultrahigh theoretical specific capacity of 3860 mAh g−1, lithium (Li) is regarded as the ultimate anode for high‐energy‐density batteries. However, the practical application of Li metal anode is hindered by safety concerns and low Coulombic efficiency both of which are resulted fromunavoidable dendrite growth during electrodeposition. This study focuses on a critical parameter for electrodeposition, the exchange current density, which has attracted only little attention in research on Li metal batteries. A phase‐field model is presented to show the effect of exchange current density on electrodeposition behavior of Li. The results show that a uniform distribution of cathodic current density, hence uniform electrodeposition, on electrode is obtained with lower exchange current density. Furthermore, it is demonstrated that lower exchange current density contributes to form a larger critical radius of nucleation in the initial electrocrystallization that results in a dense deposition of Li, which is a foundation for improved Coulombic efficiency and dendrite‐free morphology. The findings not only pave the way to practical rechargeable Li metal batteries but can also be translated to the design of stable metal anodes, e.g., for sodium (Na), magnesium (Mg), and zinc (Zn) batteries.

Potentiometric MRI of a Superconcentrated Lithium Electrolyte: Testing the Irreversible Thermodynamics Approach

“… 88 A fitting procedure based on a simple Butler–Volmer kinetic model ( Supporting Information , section S2.G) produces an effective exchange-current density that increases linearly with respect to the square root of time, traditionally consistent with a diffusion-limited surface roughening process during Li deposition. 78 , 89 , 90 This overall trend suggests that for the galvanostatic polarization experiments presented, the increase in Li surface area (and its accompanying SEI) outcompetes any increase in interfacial resistance from SEI thickening elsewhere. It is difficult to construct reference-electrode configurations that offer position-dependent information within an electrochemical cell; 40 complete transport and thermodynamic descriptions of bulk electrolytes could enable further quantitative analysis of interfacial processes.…”

Moving beyond 99.9% Coulombic efficiency for lithium anodes in liquid electrolytes

“…Systematic cyclic voltammetry experiments 50,71,72 reveal that j 0 varies greatly across different electrolytes and measurement conditions (Fig. 4b).…”

Hydrogen‐Bonding Crosslinking MXene to Highly Robust and Ultralight Aerogels for Strengthening Lithium Metal Anode

“…[ 5 ] On this basis, the Li hosts with 3D porous architecture were further utilized for achieving even Li plating/stripping by homogenizing the Li + mass transfer and localized electric field. [ 6 ] Large surface area and sufficient free space of such anode configuration bring particular benefits in minimizing the huge volume change of the anode with heavy Li metal loading. [ 7 ] These merits allow one to suppress the Li dendrite growth at high current density with less sacrifice of Li metal loading and anode kinetics.…”