| Novel Carbon - Ultrafine Silicon Composite Anode for High-Performance Lithium-Ion Batteries Dmitry Yarmolich1; Dzianis Yarmolich2; Yaroslav Odarchenko3; Carmen Murphy4; Enrico Petrucco4; Vasant Kumar5; Rumen Tomov5; 1PLASMA APP LTD, OX11 0QX, United Kingdom; 2PLASMA APP LTD, Oxford , OX11 0QX, United Kingdom; 3PLASMA APP LTD, Oxford OX11 0QX, United Kingdom; 4JOHNSON MATTHEY BATTERY MATERIALS, Reading RG4 9NH, United Kingdom; 5UNIVERSITY OF CAMBRIDGE, Cambridge, United Kingdom; PAPER: 352/Battery/Regular (Oral) SCHEDULED: 12:35/Fri. 25 Oct. 2019/Coralino ABSTRACT: Silicon (Si) has been widely considered as potential high capacity anode material in Li-ion batteries due to its desirable properties: (i) high theoretical specific capacity (1672 mA h g-1), (ii) nontoxicity and (iii) low cost and natural abundance [1]. Despite its favourable comparison to commercial graphite anodes (theoretical capacity of 372 mA h g-1), the implementation of bulk Si anode has been hindered by the large volume change during the charging and discharging cycle (~ 300%). Such structural instability results in loss of contact with the other electrode constituents and self-destruction [2]. Another adverse feature is the limited Li<sup>+</sup> ion diffusivity and electronic conductivity of bulk Si at room temperature. A scalable method of producing carbon (ultrafine silicon composite electrode) was developed using the Virtual Cathode Deposition technique [3]. As-deposited coatings contained silicon nano-crystallites encapsulated in a novel polymorph of mesoporous disordered carbon matrix. The architecture of the electrode offers close-order integration of both materials ensuring fast Li<sup>+</sup> ion diffusivity and mixed-(ionic/electronic) conductivity as well as alleviating Si volume change during cycling. The composite carbon polymorph-silicon anode tested versus Li displayed a first cycle specific capacity of more than 2000 mAh g<sup>-1</sup> retaining in the following cycles ~1200 mAh g<sup>-1</sup> at a 0.1C rate. The good cyclability (over 80 cycles) demonstrated the effectiveness of such Si - carbon encapsulation, addressing the instability issues of Si-based anodes. References: [1] P. G. Bruce, S. A. Freunberger, L. J. Hardwick and J. M. Tarascon, Nat. Mater., 2012, 11, 19–29. [2] Li B, Xiao Q, Luo Y (2018) A modified synthesis process of three dimensional sulfur/graphene aerogel as binder-free cathode for lithium-sulfur batteries. Mater Des 153:9–14 [3] D. Yarmolich, D. Virtual cathode deposition (vcd) for thin film manufacturing WO2016042530A1. (2015). |
