Supplementary Information files for Rapid microwave-assisted bulk production of high-quality reduced graphene oxide for lithium ion batteries
Graphene-based advanced electrodes with improved electrochemical properties have received increasing attention for use in lithium ion batteries (LIBs). The conventional synthesis of graphene via liquid phase exfoliation or chemical reduction of graphene oxide (GO) approaches, however, either involves prolonged processing or leads to the retainment of high-concentration oxygen functional groups (OFGs). Herein, bulk synthesis of high-quality reduced graphene oxide using microwave irradiation (MWrGO) within few seconds is reported. The electromagnetic interaction of GO with microwaves is elucidated at molecular level using reactive molecular dynamic simulations. The simulation suggests that higher power microwave irradiation results in significantly less retainment of OFGs and the formation of structural voids. The synthesized MWrGO samples are thoroughly characterized in terms of structural evolution and physicochemical properties. Specifically, a modified ID/IG-in ratio metric for Raman spectrum, wherein the intensity contribution of D’ peak is deducted from the apparent G peak, is proposed to investigate the structural evolution of synthesized MWrGO, which yields a more reliable evaluation of structural disorder over traditional ID/IG ratio. Li-ion half-cell studies demonstrate that the MWrGO is an excellent candidate for usage as high capacity anode (750.0 mAh g-1 with near-zero capacity loss) and high-performance cathode (high capacity retention of ~70% for LiCoO2 at 10 C) for LIBs.

Supplementary Information files for Rapid microwave-assisted bulk production of high-quality reduced graphene oxide for lithium ion batteries
Graphene-based advanced electrodes with improved electrochemical properties have received increasing attention for use in lithium ion batteries (LIBs). The conventional synthesis of graphene via liquid phase exfoliation or chemical reduction of graphene oxide (GO) approaches, however, either involves prolonged processing or leads to the retainment of high-concentration oxygen functional groups (OFGs). Herein, bulk synthesis of high-quality reduced graphene oxide using microwave irradiation (MWrGO) within few seconds is reported. The electromagnetic interaction of GO with microwaves is elucidated at molecular level using reactive molecular dynamic simulations. The simulation suggests that higher power microwave irradiation results in significantly less retainment of OFGs and the formation of structural voids. The synthesized MWrGO samples are thoroughly characterized in terms of structural evolution and physicochemical properties. Specifically, a modified ID/IG-in ratio metric for Raman spectrum, wherein the intensity contribution of D’ peak is deducted from the apparent G peak, is proposed to investigate the structural evolution of synthesized MWrGO, which yields a more reliable evaluation of structural disorder over traditional ID/IG ratio. Li-ion half-cell studies demonstrate that the MWrGO is an excellent candidate for usage as high capacity anode (750.0 mAh g-1 with near-zero capacity loss) and high-performance cathode (high capacity retention of ~70% for LiCoO2 at 10 C) for LIBs.

ABSTRACT Objective: To investigate the predictive value of transcranial Doppler (TCD) ultrasound for cerebral small vessel disease in elderly patients. Methods: Transcranial Doppler ultrasound and magnetic resonance imaging (MRI) were performed on 184 elderly patients with cerebral small vessel disease. The relationship of clinical characteristics and TCD ultrasound parameters with severe white matter lesions (WMLs) in MRI were investigated by univariate analysis and multivariate analysis. Results: The univariate analysis showed that age, left middle cerebral artery (MCA) mean flow velocity, right MCA mean flow velocity and mean MCA pulsatility index were significantly correlated with severe WMLs (p < 0.05). The multivariate logistic regression analysis showed that only age (odds ratio: 1.21; 95%CI: 1.10–1.36; p < 0.01) and MCA pulsatility index (dominance ratio: 1.13; 95%CI: 1.06–1.80; p = 0.02) were significantly correlated with severe WMLs. The analysis of TCD ultrasound parameters showed that when the cut-off for MCA pulsatility index was 1.04, it could identify severe WMLs. The area under the curve was 0.70 (95%CI: 0.60–0.80). The sensitivity and specificity were 63.0% and 72.0%, respectively. The positive and negative predictive values were 35.4% and 86.6%, respectively. Conclusion: The MCA pulsatility index in TCD ultrasound is significantly correlated with severe WMLs; and TCD ultrasound can guide selective MRI for the detection of WMLs.

ABSTRACT Objective: To investigate the predictive value of transcranial Doppler (TCD) ultrasound for cerebral small vessel disease in elderly patients. Methods: Transcranial Doppler ultrasound and magnetic resonance imaging (MRI) were performed on 184 elderly patients with cerebral small vessel disease. The relationship of clinical characteristics and TCD ultrasound parameters with severe white matter lesions (WMLs) in MRI were investigated by univariate analysis and multivariate analysis. Results: The univariate analysis showed that age, left middle cerebral artery (MCA) mean flow velocity, right MCA mean flow velocity and mean MCA pulsatility index were significantly correlated with severe WMLs (p < 0.05). The multivariate logistic regression analysis showed that only age (odds ratio: 1.21; 95%CI: 1.10–1.36; p < 0.01) and MCA pulsatility index (dominance ratio: 1.13; 95%CI: 1.06–1.80; p = 0.02) were significantly correlated with severe WMLs. The analysis of TCD ultrasound parameters showed that when the cut-off for MCA pulsatility index was 1.04, it could identify severe WMLs. The area under the curve was 0.70 (95%CI: 0.60–0.80). The sensitivity and specificity were 63.0% and 72.0%, respectively. The positive and negative predictive values were 35.4% and 86.6%, respectively. Conclusion: The MCA pulsatility index in TCD ultrasound is significantly correlated with severe WMLs; and TCD ultrasound can guide selective MRI for the detection of WMLs.

OTUs distribution in each sample. (XLSX 2056Â kb)

OTUs distribution in each sample. (XLSX 2056Â kb)