Title: Reducing Mg Anode Overpotential via Ion Conductive Surface Layer Formation by Iodine Additive

Abstract

Abstract Electrolytes that are able to reversibly deposit/strip Mg are crucial for rechargeable Mg batteries. The most studied complex electrolytes based on Lewis acid‐base chemistry are expensive, difficult to be synthesized, and show limited anodic stability. Conventional electrolytes using simple salts such as Mg(TFSI) ₂ can be readily synthesized, but Mg deposition/stripping in these simple salt electrolytes is accompanied by a large overpotential due to the formation of a surface layer on the Mg metal with a low Mg ion conductivity. Here the overpotential for Mg deposition/stripping in a simple salt, Mg(TFSI) ₂ ‐1,2‐dimethoxyethane (DME), electrolyte is significantly reduced by adding a small concentration of iodine (≤50 × 10 ⁻³ m ) as an additive. Mechanism studies demonstrate that an Mg ion conductive solid MgI ₂ layer is formed on the surface of the Mg metal and acts as a solid electrolyte interface. With the Mg(TFSI) ₂ ‐DME‐I ₂ electrolyte, a very small voltage hysteresis is achieved in an Mg‐S full cell.

Authors:

Li, Xiaogang ^[1]; Gao, Tao ^[2]; Han, Fudong ^[2]; Ma, Zhaohui ^[2]; Fan, Xiulin ^[2]; Hou, Singyuk ^[2]; Eidson, Nico ^[2]; Li, Weishan ^[3]; Wang, Chunsheng ^[2]

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+ Show Author Affiliations

1. Univ. of Maryland, College Park, MD (United States); South China Univ. of Technology (SCUT), Guangzhou (China)
2. Univ. of Maryland, College Park, MD (United States)
3. South China Univ. of Technology (SCUT), Guangzhou (China)

Publication Date:

Tue Oct 24 00:00:00 EDT 2017

Research Org.:

Univ. of Maryland, College Park, MD (United States). Energy Frontier Research Center (EFRC) Nanostructures for Electrical Energy Storage (NEES)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1469930

Alternate Identifier(s):

OSTI ID: 1402538

Grant/Contract Number:  

SC0001160; DESC0001160

Resource Type:

Accepted Manuscript

Journal Name:

Advanced Energy Materials

Additional Journal Information:

Journal Volume: 8; Journal Issue: 7; Related Information: NEES partners with University of Maryland (lead); University of California, Irvine; University of Florida; Los Alamos National Laboratory; Sandia National Laboratories; Yale University; Journal ID: ISSN 1614-6832

Publisher:

Wiley

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE; electrochemistry; iodine additive; Mg(TFSI)2‐DME simple salt electrolyte; reduce overpotential; sulfur