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

Shun Li,Dongmei Qi,Jianguo Huang,Ming Yang,Guijin He

doi:10.3390/ma14123411

Shun Li, Dongmei Qi + Show 3 more

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https://doi.org/10.3390/ma14123411

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Journal: Materials	Publication Date: Jun 20, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: Zhejiang A & F University, Zhejiang University

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.

Highlights

Lithium-ion batteries (LIBs) are regarded as one of the most practical and effective technologies for the development of electric vehicles, mobile devices, and reproducible energy integration [1,2]
The MnO2 nanosheets were uniformly immobilized on the surfaces of the ultrathin TiO2-coated carbon nanofibers or on the nanofibrous carbon to acquire MnO2-TiO2-carbon (Scheme 1a–d) and MnO2-carbon composites (Scheme 1a–f)
The three-dimensional network structures of the nanocomposite were perfectly inherited from the original cellulose substances, and the closely-packed MnO2 sheets were evenly immobilized on the surfaces of the titania-coated carbon nanofibers (Figure 1b)

Summary

Introduction

Lithium-ion batteries (LIBs) are regarded as one of the most practical and effective technologies for the development of electric vehicles, mobile devices, and reproducible energy integration [1,2]. Adopted commercial graphite anode materials deliver a relatively low specific capacity of 372 mAh g−1, which are unable to satisfy the increasing requirements for high energy storage [5]. Compared with conventional commercialized graphite anodes, transition metal oxides have caused a great deal of interest thanks to their high theoretical capacities and reliable discharging rates [6,7,8,9,10,11]. The practical applications of MnO2-based anode materials are greatly limited by their poor intrinsic electric conductivity (~10−7–10−8 S cm−1) and severe volume expansion and pulverization of MnO2 matter from repeated charge/discharge cycles [14,15]

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