A Cellulose-Derived Nanofibrous MnO2-TiO2-Carbon Composite as Anodic Material for Lithium-Ion Batteries

Abstract

A bio-inspired nanofibrous MnO2-TiO2-carbon composite was prepared by utilizing natural cellulosic substances (e.g., ordinary quantitative ashless filter paper) as both the carbon source and structural matrix. Mesoporous MnO2 nanosheets were densely immobilized on an ultrathin titania film precoated with cellulose-derived carbon nanofibers, which gave a hierarchical MnO2-TiO2-carbon nanoarchitecture and exhibited excellent electrochemical performances when used as an anodic material for lithium-ion batteries. The MnO2-TiO2-carbon composite with a MnO2 content of 47.28 wt % exhibited a specific discharge capacity of 677 mAh g−1 after 130 repeated charge/discharge cycles at a current rate of 100 mA g−1. The contribution percentage of MnO2 in the composite material is equivalent to 95.1% of the theoretical capacity of MnO2 (1230 mAh g−1). The ultrathin TiO2 precoating layer with a thickness ca. 2 nm acts as a crucial interlayer that facilitates the growth of well-organized MnO2 nanosheets onto the surface of the titania-carbon nanofibers. Due to the interweaved network structures of the carbon nanofibers and the increased content of the immobilized MnO2, the exfoliation and aggregation, as well as the large volume change of the MnO2 nanosheets, are significantly inhibited; thus, the MnO2-TiO2-carbon electrodes displayed outstanding cycling performance and a reversible rate capability during the Li+ insertion/extraction processes.

Lignin-Based Mesoporous Hollow Carbon@MnO2 Nanosphere Composite as an Anodic Material for Lithium-Ion Batteries

“…The peak intensity of the carbon phase in the two lignin-based MnO 2 composites was weaker than those of the lignin-carbon and L-C-NSs. Interestingly, it was very hard to find the graphitic carbon in the two composites, which was ascribed to the consumption of the carbon during the generation of MnO 2 nanoparticles [30]. The structure properties of the corresponding samples were further confirmed by Raman spectra, as revealed in Figure 4c.…”

“…The methods (including the specimens preparation methods for electron microscope observation) and apparatus for the tests of field emission scanning electron microscopy (FE-SEM, Hitachi SU-8010, HITACHI, Tokyo, Japan), selected area electron diffraction (SAED, JEM-2100F, JEOL, Tokyo, Japan), transmission electron microscopy (TEM, Hitachi HT-7700, HITACHI, Tokyo, Japan), Raman spectrometer (HORIBA, Paris, France), X-ray photoelectron spectra (XPS, VG Escalab Mark 2, VG Instruments, Manchester, UK), and the N 2 adsorption-desorption analyses (Micromeritics ASAP-2020 analyzer, Micromeritics, Norcross, GA, USA) were conducted in similar ways in line with our previous report [30].…”

“…The two weak peaks of the L-C-NSs@MnO 2 and lignin-carbon@MnO 2 composites appeared at 37.3 • and 65.6 • and were indexed to the (−111) and (020) planes of the α-MnO 2 , respectively (JCPDS#. 80-1098) [30,32]. Regarding the L-C-NSs and lignin-carbon materials, two broad diffraction peaks are indexed to graphitic carbon located at 24 • (002 plane) and 44 • (100 plane) [33].…”

“…Figure 6a shows the CV curves of the L-C-NSs@MnO2 composite for the first four discharge/charge cycles. In the initial cathodic curve, a broad peak at lower voltage and a mild peak near 0.8 V were ascribed to the generation of a solid electrolyte interface (SEI) layer and the reduction of MnO2 with Li ions [30,39]. Two anodic…”

“…In our previous work, the MnO 2 -TiO 2 -carbon nanofiber composites were fabricated by using natural cellulose matter as a carbon source and structural scaffold. This nanocomposite with interwoven network structures and a large MnO 2 content displayed a capacity of 677 mAh g −1 as cycled to 130 cycles at 0.1 A g −1 [30]. Therefore, the biomass-derived carbon electrodes showed superior electrochemical activities because of their porous structures and superior electrical conductivity, which facilitated the full contact of the electrode and electrolyte together with the fast transport of e − and Li + during the Li/Li + processes.…”