TY - JOUR

T1 - Lifetime vs. rate capability

T2 - Understanding the role of FEC and VC in high-energy Li-ion batteries with nano-silicon anodes

AU - Jaumann, Tony

AU - Balach, Juan

AU - Langklotz, Ulrike

AU - Sauchuk, Viktar

AU - Fritsch, Marco

AU - Michaelis, Alexander

AU - Teltevskij, Valerij

AU - Mikhailova, Daria

AU - Oswald, Steffen

AU - Klose, Markus

AU - Stephani, Guenter

AU - Hauser, Ralf

AU - Eckert, Jürgen

AU - Giebeler, Lars

PY - 2017/1/1

Y1 - 2017/1/1

N2 - Fluoroethylene carbonate (FEC) and vinylene carbonate (VC) are the most frequently used electrolyte components to enhance the lifetime of anode materials in Li-ion batteries, but for silicon it is still ambiguous when FEC or VC is more beneficial. Herein, a nanostructured silicon/carbon anode derived from low-cost HSiCl3 is tailored by the rational choice of the electrolyte component, to obtain an anode material outperforming current complex silicon structures. We demonstrate highly reversible areal capacities of up to 5 mA h/cm2 at 4.4 mg/cm2 mass loading, a specific capacity of 1280 mA h/gElectrode, a capacity retention of 81% after 500 deep-discharge cycles versus lithium metal and successful full-cell tests with high-voltage cathodes meeting the requirements for real application. Electrochemical impedance spectroscopy and post-mortem investigation provide new insights in tailoring the interfacial properties of silicon-based anodes for high performance anode materials based on an alloying mechanism with large volume changes. The role of fluorine in the FEC-derived interfacial layer is discussed in comparison with the VC-derived layer and possible degradation mechanisms are proposed. We believe that this study gives a valuable understanding and provides new strategies on the facile use of additives for highly reversible silicon anodes in Li-ion batteries.

AB - Fluoroethylene carbonate (FEC) and vinylene carbonate (VC) are the most frequently used electrolyte components to enhance the lifetime of anode materials in Li-ion batteries, but for silicon it is still ambiguous when FEC or VC is more beneficial. Herein, a nanostructured silicon/carbon anode derived from low-cost HSiCl3 is tailored by the rational choice of the electrolyte component, to obtain an anode material outperforming current complex silicon structures. We demonstrate highly reversible areal capacities of up to 5 mA h/cm2 at 4.4 mg/cm2 mass loading, a specific capacity of 1280 mA h/gElectrode, a capacity retention of 81% after 500 deep-discharge cycles versus lithium metal and successful full-cell tests with high-voltage cathodes meeting the requirements for real application. Electrochemical impedance spectroscopy and post-mortem investigation provide new insights in tailoring the interfacial properties of silicon-based anodes for high performance anode materials based on an alloying mechanism with large volume changes. The role of fluorine in the FEC-derived interfacial layer is discussed in comparison with the VC-derived layer and possible degradation mechanisms are proposed. We believe that this study gives a valuable understanding and provides new strategies on the facile use of additives for highly reversible silicon anodes in Li-ion batteries.

KW - FEC

KW - Li-ion battery

KW - Silicon anode

KW - VC

UR - http://www.scopus.com/inward/record.url?scp=84989277414&partnerID=8YFLogxK

U2 - 10.1016/j.ensm.2016.08.002

DO - 10.1016/j.ensm.2016.08.002

M3 - Article

AN - SCOPUS:84989277414

VL - 6.2017

SP - 26

EP - 35

JO - Energy Storage Materials

JF - Energy Storage Materials

SN - 2405-8297

IS - January

ER -