Carbon Coating of Si Thin Flakes and Negative Electrode Properties in Lithium-Ion Batteries

Abstract

To reduce the high irreversible capacity (Q irr ) of Si thin flake (Si-LP) negative electrode, carbon-coated Si-LPs were prepared using citric acid as a precursor and their charge/discharge properties were investigated as negative electrodes in lithium-ion batteries. The carbon-coated powder was homogeneously coated with a thin carbon layer (8-10 and 6-8 nm in thickness for Si-LPs heat-treated at 600 and 700°C, respectively, 14 wt% for each). The irreversible capacity Q irr was successfully reduced to about a half (ca. 1100 mAh g −1 ) of that of the pristine Si-LP (2336 mAh g −1 ), though the cycleability was slightly deteriorated. The cycleability of Si-LP@Cs was significantly improved by the addition of 10 wt% VC in the electrolyte solution. Si-LP@C(700°C) kept high discharge capacities over 2000 mAh g −1 even after 50 cycles with a reduced Q irr of ca. 1300 mAh g −1 compared with the pristine Si-LP (ca. 2450 mAh g −1 ).

Silicon-based nanosheets synthesized by a topochemical reaction for use as anodes for lithium ion batteries

“…The broad peaks indicate that the SNS are either nanosized or amorphous, which is consistent with the Si thin flake prepared by a physical vapor Nano Res. deposition (PVD) method by Okubo [27]. In this work, SNS is amorphous, which is further confirmed by Raman spectra (Fig.…”

“…Figures 2(c) and 2(d) show the SEM images of HO-SNS-W, as a typical example, after removal of Sn nanoparticles. Different from the previous SNS [27,34], which are completely planar in structure and easily stackable with one another, the peapod-like SNS shows a corrugated morphology with abundant void spaces. Furthermore, almost every single nanosheet is split into two or more thinner ones.…”

“…For example, Si thin films, typical 2D materials, show better cycling performance compared to powder-based anodes. Other 2D Si-based materials have also been fabricated, including nanoribbons [26], thin flakes [27,28], and nanosheets [29][30][31]. However, the main disadvantage of 2D Si-based materials is that their preparation methods are complicated, involving rigorous reaction conditions (high temperature and/or high vacuum), high cost, toxic and/or inflammable reactants, complicated reaction processes and low productivity.…”

Silicon Nano-flake Powder as an Anode for The Next Generation Lithium-ion Batteries: Current Status and Challenges

“…31 A carbon source, e.g. citric acid, was impregnated in Si-LP powder, and fired at 600, 700, and 800°C to coat the Si-LP powder with thin carbon layer.…”

Stabilization of Si Negative Electrode by Li Pre-doping Technique and the Application to a New Energy Storage System

“…In the previous study, we demonstrated that the Si-CAP cell was improved by using additives, such as vinylene carbonate (VC) and fluoroethylene carbonate (FEC), and vacuum pressure impregnation (VPI) treatment during the Li pre-doping step. 15 The treatments effectively promoted preferred solid-electrolyte interface (SEI) film formation on the surface of the Si nanoparticles and homogeneous Li predoping into its bulk, which suppressed rapidly fading capacity by electrolyte decomposition 18,19 and a large volume change of Si. [20][21][22] In addition to the Li pre-doping technique, the limitation of Si NE capacity by that of the AC positive electrode (PE) in the hybrid capacitor system was also able to extend the cycle life of the Si-CAP; however, the effects on the charge/discharge properties of Si-CAP were only reported for short cycle periods (up to 50 cycles).…”