Revealing Principles for Design of Lean-Electrolyte Lithium Metal Anode via In Situ Spectroscopy

Abstract

Lean-electrolyte conditions are highly pursued for practical lithium (Li) metal batteries. The previous studies on the Li metal anodes, in general, exhibited good stability with a large excess of electrolyte. However, the targeted design of Li hosts under relatively low electrolyte conditions has been rarely studied so far. Herein, we have shown that electrolyte consumption severely affects the cycling stability of Li metal anode. Considering carbon hosts as typical examples, we innovatively employed in situ synchrotron X-ray diffraction, in situ Raman spectroscopy, and theoretical computations to obtain a better understanding of the Li nucleation/deposition processes. We also showed the usefulness of in situ electrochemical impedance spectra to analyze interfacial fluctuation at the Li/electrolyte interface, together with nuclear magnetic resonance data to quantify electrolyte consumption. We have found that uneven Li nucleation/deposition and the crack of surface-area-derived solid-electrolyte interface (SEI) layer both lead to a great consumption of electrolyte. Then, we suggested a design principle for Li host to overcome the electrolyte loss, that is, uneven growth of the Li structure and the crack of the SEI layer must be simultaneously controlled. As a proof of concept, we demonstrated the usefulness of a 3D low-surface-area defective graphene host (L-DG) to control Li nucleation/deposition and stabilize the SEI layer, contributing to a highly reversible Li plating/ stripping. As a result, such a Li host can achieve stable cycles (e.g., 1.0 mAh cm −2 ) with a low electrolyte loading (10 μL). This work demonstrates the necessity to design Li metal anodes under lean-electrolyte conditions and brings Li metal batteries a step closer to their practical applications.

Mechanism for Zincophilic Sites on Zinc‐Metal Anode Hosts in Aqueous Batteries

“…This finding demonstrates the improved nucleation kinetics for CnC HS over C HS, and confirms the impact on overall nucleation kinetics from the nitrogen nucleation sites. [ 37,61 ] As is shown in Figure 4e, for galvanostatic cycling testing under various current densities, CnC HS exhibited boosted stability over C HS. Specifically, during an areal capacity of 1 mAh cm −2 under a current density of 2 mA cm −2 , large voltage hysteresis occurred in the cycling profiles of C HS, while that for CnC HS remained stable.…”

Co2+/3+/4+‐Regulated Electron State of Mn‐O for Superb Aqueous Zinc‐Manganese Oxide Batteries

“…[ 1–3 ] In terms of energy storage mechanism, compared to monovalent metal ions (such as Li + , Na + ), Zn 2+ allows multiple ionic charges to transport carriers. [ 4,5 ] However, practical application of ZIBs is plagued by the obstacles in cathodes, such as poor cycle stability caused by irreversible lattice distortion and low rate caused by poor conductivity. [ 6–8 ]…”

Regulating the Solvation Sheath of Li Ions by Using Hydrogen Bonds for Highly Stable Lithium–Metal Anodes

“…The rising of energy demand is calling for alternatives of traditional lithium‐ion batteries (LIBs) [1–10] . In this regard, the lithium‐metal batteries (LMBs) provide a new possibility for high energy density systems [8, 11–18] by using Li metal as anodes, due to its ultrahigh theoretical capacity (3860 mAh g −1 ) and low electrochemical potential (−3.04 V vs. the standard hydrogen electrode). However, lithium metal is extremely reactive with most organic electrolytes, [19, 20] leading to low coulombic efficiency (CE) [21–28] …”