Correlation between Li Plating Behavior and Surface Characteristics of Carbon Matrix toward Stable Li Metal Anodes

Abstract

anodes. These new anodes promise an almost 100% increase in practical energy density compared to those of conventional LIB counterparts. [3][4][5][6][7][8][9] While developing cathodes for the next-generation batteries has made a significant progress, relatively fewer research efforts have thus far been devoted to Li metal anodes because of the formation of Li dendrites which is considered a critical drawback instigating devastating safety issues of batteries. [10] Along with recent studies on Li plating behaviors, there have been renewed interests in developing Li metal anodes. [11][12][13] In particular, the dendrite-free Li metal anode was made possible by rationally designing the electrolyte composition and electrode morphologies. [14,15] Nevertheless, the current Li metal anodes are far from being viable because of several reasons. Namely, (1) the dendritic Li emerges when the current density raises above the percolation value; (2) the Coulombic efficiencies (CEs) of Li metal anodes are too low to maintain good cyclic stability of batteries; and (3) the design of Li metal anodes is still inadequate, making it difficult to integrate into the existing LIB configurations, such as pouch and cylindrical cells. [12] Most of the strategies currently exercised for dendrite-free Li metal anodes usually fail to resolve all the above mentioned issues. For example, the all-solid-state Li-metal battery requires certain prestress to reduce the interfacial resistance between the solid-state electrolyte and the electrode, but such a prestress is difficult to apply on pouch cells. [16,17] The feasibility of artificial solid electrolyte interphase (SEI) protection on Li foil remains doubtful because the Li foil alone cannot be used as current collector in practical cells due to its hostless nature and huge volume changes during the repeated cycles. [11,18] Among all potential strategies, the incorporation of conductive substrates to function as both the Li host and current collector is considered an ideal approach for further development of practical Li metal anodes. [19] The growth of Li dendrites at high current densities was mitigated by means of reduced local current densities using conductive substrates. [12] Moreover, the conductive substrates also functioned as the current collector, which is compatible with the existing LIB configurations. While copper has been widely studied as the matrix material for hosting Li metal, carbon is considered a more promising candidate than copper Carbonaceous materials are widely employed to host Li for stable and safe Li metal batteries while relatively little effort is devoted to tailoring the surface properties of carbon to facilitate uniform Li plating. Herein, the correlation between Li plating behavior and the surface characteristics of electrospun porous carbon nanofibers (PCNFs) is systemically elucidated through experiments and theoretical calculations. It is revealed that the neat carbon surface suffers from severe lattice mismatch with Li metal, hindering uniform Li plating....

Large‐Scale Modification of Commercial Copper Foil with Lithiophilic Metal Layer for Li Metal Battery

“…In sharp contrast, the pure Cu collector exhibited a fluctuant CE after only 100 laps. The cyclic performance on Cu‐Ag collector was superior to most recent reports including some planar or 3D collectors . When the current density was further enhanced to 2.0 mA cm −2 and even reached 3.0 mA cm −2 , the CE value on the Ag‐Cu collectors respectively remained at ≈99.72% (for 270 cycles shown in Figure c, 2.0 mA cm −2 ) and ≈98.23% (for 200 cycles shown in Figure d, mA cm −2 ), respectively.…”

Sodiophilically Graded Gold Coating on Carbon Skeletons for Highly Stable Sodium Metal Anodes

“…[4,6,7] However, Na-metal batteries (NMBs) have several challenges due to the presence of metallic Na, including, 1) the nonuniform deposition of Na which leads to the uncontrollable growth of Na dendrite, eventually short-circuiting the batteries, 2) the large volume changes occurring during plating/stripping cycles because of its hostless nature, and 3) the formation of unstable solid electrolyte interphase (SEI) layers at the expense of continuous depletion of the electrolyte. [3,7,8] In fact, all these issues are interrelated and lower the coulombic efficiency (CE), trigger serious safety hazards, and are ultimately responsible for the short lifespan of NMBs. [7,9,10] Many efforts have been directed to circumventing these challenges, including the optimization of electrolyte composition, [11][12][13] the construction of artificial SEI layers, [14][15][16] the modulation of morphology/structure of current collectors and hosts, [17][18][19][20][21][22][23][24] the building of interlayers, [10,25] and the use of solidstate electrolytes.…”

S‐Doped Graphene‐Regional Nucleation Mechanism for Dendrite‐Free Lithium Metal Anodes

“…[9,10] During the past half-century, many up-and-coming methods have been carried out to suppress dendrite growth and achieved partially success. [21][22][23] However, the pristine graphene (PG) shows poor performances in the actual application. The former two strategies are based primarily on suppressing the protrusions, while the last one mainly focuses on modulating the initial nucleation process of dendrite, before the extension of dendrites into the electrolyte.…”

“…Graphene, who possesses very high specific surface area, shows great advantage on its potential application in lithium metal anode field. [21][22][23] However, the pristine graphene (PG) shows poor performances in the actual application. [24][25][26] Doping or modulating the graphene can adjust its performance which has already made some Lithium metal is the most promising anode material for next-generation batteries, owing to its high theoretical specific capacity and low electrochemical potential.…”