Phenyl-rich silicone oil as a precursor for SiOC anode materials for long-cycle and high-rate lithium ion batteries. Issue 7 (29th January 2016)

• Record Type: Journal Article
• Authors: Halim, Martin; Hudaya, Chairul; Kim, A-Young; Lee, Joong Kee
• Is Part Of: Journal of materials chemistry. Volume 4:Issue 7(2016)
• Page Start: 2651
• Page End: 2656
• Publication Date: 2016-01-29
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c5ta09973k
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Silicon oxycarbide (SiOC) is gaining increasing attention as a promising anode material for lithium ion batteries due to its higher reversible capacity compared to incumbent graphite. Abstract : Silicon oxycarbide (SiOC) is gaining increasing attention as a promising anode material for lithium ion batteries due to its higher reversible capacity compared to incumbent graphite. The kinetic processes at a SiOC anode result in rapid capacity fading even at a relatively low current density, thereby hindering its commercialization. Herein, a distinctive, phenyl-rich silicone oil is used as a precursor for producing SiOC anode materials via simple pyrolysis. We find that only silicone oil with phenyl-rich rings can be converted into SiOC materials. The phenyl group was crucial for carbon incorporation to allow Si–O–C bonding and the formation of a free-carbon phase. The resulting SiOC anode exhibited stable cyclability up to 250 cycles, with a discharge capacity of 800 mA h g −1 at a current density of 200 mA g −1 . The remarkable cycle performance of SiOC was correlated with its low dimensional expansion (7%) during lithiation, which maintains its structure over cycling. Rate capability tests showed a highly stable performance with a maximum discharge capacity of 852 mA h g −1 at a current density of 100 mA g −1 . When the discharge current density was increased 64-fold, the reversible capacity of the SiOC anode was 90% of its maximum capacity, 772 mA h g −1 . The excellent electrochemical performance of SiOC could be attributed to the rapid mobility of Li + within the SiOC matrix, as indicated by a Li + diffusion coefficient of 5.1 × 10 −6 cm 2 s −1 .