Substoichiometric Silicon Nitride - An Anode Material for Li-ion Batteries Promising High Stability and High Capacity

Asbjørn Ulvestad; Hanne F Andersen; Ingvild J T Jensen; Trygve T Mongstad; Jan Petter Mæhlen; Øystein Prytz; Martin Kirkengen

doi:10.1038/s41598-018-26769-8

Substoichiometric Silicon Nitride - An Anode Material for Li-ion Batteries Promising High Stability and High Capacity

Sci Rep. 2018 Jun 5;8(1):8634. doi: 10.1038/s41598-018-26769-8.

Authors

Asbjørn Ulvestad¹, Hanne F Andersen², Ingvild J T Jensen³, Trygve T Mongstad², Jan Petter Mæhlen², Øystein Prytz⁴, Martin Kirkengen²

Affiliations

¹ Department of Battery Technology, Institute for Energy Technology, P.O. Box 40, NO-2027, Kjeller, Norway. asbjorn.ulvestad@ife.no.
² Department of Battery Technology, Institute for Energy Technology, P.O. Box 40, NO-2027, Kjeller, Norway.
³ SINTEF Industry, P.O. Box 124 Blindern, NO-0314, Oslo, Norway.
⁴ Department of Physics, Centre for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048 Blindern, NO-0316, Oslo, Norway.

Abstract

Silicon is often regarded as a likely candidate to replace graphite as the main active anode material in next-generation lithium ion batteries; however, a number of problems impacting its cycle stability have limited its commercial relevance. One approach to solving these issues involves the use of convertible silicon sub-oxides. In this work we have investigated amorphous silicon sub-nitride as an alternative convertible silicon compound by comparing the electrochemical performance of a-SiN_x thin films with compositions ranging from pure Si to SiN_0.89. We have found that increasing the nitrogen content gradually reduces the reversible capacity of the material, but also drastically increases its cycling stability, e.g. 40 nm a-SiN_0.79 thin films exhibited a stable capacity of more than 1,500 mAh/g for 2,000 cycles. Consequently, by controlling the nitrogen content, this material has the exceptional ability to be tuned to satisfy a large range of different requirements for capacity and stability.