Recent Advances of Electroplating Additives Enabling Lithium Metal Anodes to Applicable Battery Techniques

Abstract

Lithium (Li) metal batteries have long been deemed as the representative high‐energy‐density energy storage systems due to the ultrahigh theoretical capacity and lowest electrochemical potential of Li metal anode. Unfortunately, the intractable dendritic Li deposition during cycling greatly restrains the large‐scale applications of Li metal anodes. Recent advances have been explored to address this issue, among which a specific class of electrolyte additives for electroplating is deeply impressive, as they are economic and pragmatic. Different from the conventional additives that construct solid electrolyte interphase (SEI) layer on anodes, they make dendrite‐free Li metal anodes feasible through altering Li plating behavior. In this research news article, the interlinked principles between industrial electroplating and Li deposition are firstly illustrated. The featured effects of electroplating additives on regulating Li plating morphology are also summarized and mainly divided into three categories: co‐deposition with Li cation, coordination with Li cation, and leveling effect of Li films. Furthermore, the mechanism exploration or derivative use of electroplating additive for dendrite suppression and potential research directions are proposed, with emphasizing that industrial electroplating might enable Li metal anode to scalable battery techniques and spread to metal battery systems beyond Li.

Lithium‐Metal Batteries via Suppressing Li Dendrite Growth and Improving Coulombic Efficiency

“…Additives have been extensively studied for stabilizing Li metal anode and they are considered the most cost‐effective compared to other strategies. [ 135 ] By altering Li + solvation, optimizing the SEI composition, and regulating the Li plating process, additives can significantly improve the CE and achieve dendrite‐free deposition in LMBs. [ 136 ] LiNO 3 and other nitrates, such as Cu(NO 3 ) 2 and AgNO 3 , have been used in many electrolytes to achieve high CE.…”

In Situ Formation of Polycyclic Aromatic Hydrocarbons as an Artificial Hybrid Layer for Lithium Metal Anodes

“…With the rapid development of portable electronics and electric vehicles, mileage anxiety is stimulating extensive studies in high-energy batteries. − Lithium (Li) metal anodes receive increasing attention because of the highest capacity (3860 mAh g –1 ) and the lowest reduction potential (−3.04 V vs standard hydrogen electrode). , However, Li metal shows high reactivity and readily forms a solid electrolyte interphase (SEI) when exposed to a liquid electrolyte. , As the plating/stripping of Li metal causes the volume changes, the local properties of the internal electrode surface and electrolyte unavoidably lead to some nonuniformity of current or voltage distributions, which may also be compounded by uncontrollable chaotic reasons. ,, A dynamic change of volume will amplify the difference in local voltage and current density . When a local voltage fluctuates over the required nucleation overpotential, the deposition of Li metal is initiated. − Because of fields concentration and no SEI coating, the new embryo tends to self-strengthen the advantage of growth, forming the dendritic Li metal. , As a result, the formation of dendrites leads to poor cyclability, low Coulombic efficiency (CE), and even safety issues. − …”

“…), and artificial protective “skin” , have been proposed to create Li-absorbing sites or homogenize the nucleation and growth of Li metal. In addition to these successful strategies, some wisdom that has been gained in conventional metal plating is also applicable to the deposition of Li metal. , A crucial step to avoid the dendrite growth is to suppress the advantages of tip/edge growth. , The formation of SEI should be self-limiting . When additives are absorbed to Li metal, any physical effects or chemical conversion should immediately lead to a passivation layer, which shuts down the self-amplifying electrocrystallization. − Recently, in situ formation of artificial SEI via electrolyte additives has achieved rapid progress.…”

“…4,5 However, Li metal shows high reactivity and readily forms a solid electrolyte interphase (SEI) when exposed to a liquid electrolyte. 6,7 As the plating/ stripping of Li metal causes the volume changes, 8 the local properties of the internal electrode surface and electrolyte unavoidably lead to some nonuniformity of current or voltage distributions, which may also be compounded by uncontrollable chaotic reasons. 2,9,10 A dynamic change of volume will amplify the difference in local voltage and current density.…”

“…In addition to these successful strategies, some wisdom that has been gained in conventional metal plating is also applicable to the deposition of Li metal. 6,36 A crucial step to avoid the dendrite growth is to suppress the advantages of tip/edge growth. 37,38 The formation of SEI should be selflimiting.…”