Supporting information 3D porous MXene (Ti 3 C 2 )/reduced graphene oxide hybrid s for advanced lithium storage Zhiying Ma,, Xufeng Zhou,*, Wei Deng,, Da Lei,, and Zhaoping Liu *,. Key Laboratory of Graphene Technologies and Applications of Zhejiang Province and Advanced Li-ion Battery Engineering Lab, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Zhejiang 315201, P. R. China.. University of Chinese Academy of Sciences, 19 A Yuquan Rd, Shijingshan District, Beijing, 100049, P. R. China.. * Corresponding author. Tel/Fax: +86-574-8668-5096. E-mail address: liuzp@nimte.ac.cn (Z. Liu); zhouxf@nimte.ac.cn (X. Zhou). S-1
Figure S1 (a) The XRD patterns of Ti 3 AlC 2, Ti 3 C 2 and Ti 3 C 2 -TMAOH. (b-d) SEM images of Ti 3 AlC 2, Ti 3 C 2, and Ti 3 C 2 -TMAOH, respectively. XRD pattern of the initial MAX precursor can be indexed to Ti 3 AlC 2. When Ti 3 AlC 2 powders were dealt with HF solution for 24 h, the XRD pattern shows that most of the nonbasal plane peaks of Ti 3 AlC 2, most notably the most intense peak at about 2θ=39, disappear. On the other hand, the (002), (004) and (006) diffraction is broadened and shifts to lower angles compared to their location before treatment, which indicates Al atoms were removed from Ti 3 AlC 2. After intercalation of TMAOH, the (002) peak becomes dominant and shifts to even lower angle, implying the interlayer spacing of Ti 3 C 2 was enlarged due to the intercalation of TMA + ions into the layers. Furthermore, the SEM images also show how the basal planes of Ti 3 AlC 2 particle (Figure S1b) spread apart as a result of the HF treatment (Figure S1c). After the intercalation of TMAOH into the Ti 3 C 2 T X layers, the sheet-like structure (Figure S1d) of Ti 3 C 2 T X becomes more evident. S-2
Figure S2 Digital photographs of (a) pure Ti 3 C 2 solution and (b) Ti 3 C 2 solution with NH 4 HCO 3. Digital photographs of (c) pure GO solution and (d) GO solution with NH 4 HCO 3. Digital photographs of (e) GO-Ti 3 C 2 solution and (f) GO-Ti 3 C 2 solution with NH 4 HCO 3. S-3
Figure S3 (a-e) High-resolution XPS-C1s spectra of pure GO, rgo, P-Ti 3 C 2, Ti 3 C 2 and Ti 3 C 2 -rgo. (f) High-resolution XPS-Ti2p spectra of pure Ti 3 C 2 and Ti 3 C 2 -rgo. S-4
Figure S4 EDS-mapping images of Ti 3 C 2 -rgo : (a) Ti, (b) C, (c) O, (d) F, (e) N and (f) overlay of Ti, C, O, F and N. S-5
Figure S5 (a, b) Digital photographs of 1-1-Ti 3 C 2 -rgo and electrode. (c) Cross-section SEM image of 1-1-Ti 3 C 2 -rgo. (d) SEM-EDS element content analysis results of Ti, C, Al, O, F and N. S-6
Figure S6 (a) SEM image of Ti 3 C 2 flakes. (b) The size distribution of Ti 3 C 2 flakes. (c) AFM image of Ti 3 C 2 flakes. (d) The height profile along the white dash line in panel c. S-7
Figure S7 (a-f) Cross-section SEM images of Ti3C2, 4-1-Ti3C2-rGO, 3-1-Ti3C2-rGO, 2-1-Ti3C2-rGO, 1-2-Ti3C2-rGO and rgo, respectively. The cross-section images (Figure S7b-f) of various s are porous due to the addition of rgo, except the dense stacked MXene (Figure S7a). Furthermore, with the amount of rgo increases in the hybrid, the becomes thicker, which is because graphene sheets can help the hybrid to construct more open structure. S-8
Figure S8 (a-g) Nitrogen adsorption/desorption isotherms of Ti 3 C 2, 4-1-Ti 3 C 2 -rgo, 3-1-Ti 3 C 2 -rgo, 2-1-Ti 3 C 2 -rgo, 1-1-Ti 3 C 2 -rgo, 1-2-Ti 3 C 2 -rgo and rgo, respectively. (h) The specific surface area of different samples. S-9
Table S1. Composition and conductivity of various electrodes. Samples Thickness (µm) Resistance (Ω/ ) Conductivity (S/cm) Ti 3 C 2 1.94 1.8 2863 4-1-Ti 3 C 2 -rgo 18 8.4 67 3-1-Ti 3 C 2 -rgo 30 12.8 26 2-1-Ti 3 C 2 -rgo 32 20.2 15.5 1-1-Ti 3 C 2 -rgo 31 25 12.9 1-2-Ti 3 C 2 -rgo 48 46 4.53 rgo 242 25.2 1.64 The conductivities of the s were measured by four-probe method. The pure MXene has the maximal conductivity (2863 S/cm), while the conductivity of pure rgo is the lowest (1.64 S/cm) among all s. Furthermore, when the amount of rgo increases in the hybrid, the conductivity of the tends to decrease, which is because the relatively poor conductivity of rgo sheets increases the electron transfer resistance of the hybrid. S-10
Figure S9 (a) The equivalent circuit of EIS spectra (Figure 6c). (b) Fitting EIS results of all samples. S-11
Table S2. Comparison of the Rate Performance of Various MXene-Based Anode Materials Capacity 1 Capacity 2 Capacity Current 1 Current 2 Electrode Materials (ma g -1 (C 1 ) ) (mah g -1 (A g -1 (C 2 ) Retention Ref. ) ) (mah g -1 ) (C 2 /C 1 ) In-Ti 3 C 2 T X nanoparticles Ti 3 C 2 T X /CNTs Porous-Ti 3 C 2 T X /CNT Ti 3 C 2 T X /NiCo 2 O 4 PVP-Sn(IV)@Ti 3 C 2 nanoparticles SnO 2 -Ti 3 C 2 nanoparticles 3D Ti 3 C 2 -rgo 0.026 210 2.6 69 0.33 1 0.16 400 0.64 250 2 0.16 450 3.2 200 0.44 3 0.16 1050 3 320 0.31 4 0.1 750 3 250 0.33 5 0.1 353.9 1 50 0.14 6 0.1 275 4 98 0.36 This work S-12
Table S3. Comparison of the Cycling Stability of Various MXene-Based Anode Materials Electrode Materials Current density (A/g) Cycle number Reversible Capacity (mah g -1 ) Capacity retention (%) Ref. In-Ti 3 C 2 T X nanoparticles Ti 3 C 2 /CNTs Porous-Ti 3 C 2 T X /CNT Ti 3 C 2 T X /NiCo 2 O 4 PVP-Sn(IV)@Ti 3 C 2 nanoparticles SnO 2 -Ti 3 C 2 nanoparticles 3D Ti 3 C 2 -rgo 0.78 100 88 ~ 100 1 0.16 300 428.1 > 100 2 0.16 100 500 > 100 3 0.32 100 1200 > 100 4 0.5 200 544 94.3 5 0.3 300 347 < 90 6 1 1000 200 > 100 This work S-13
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