Si/Ti₂O₃/Reduced Graphene Oxide Nanocomposite Anodes for Lithium-Ion Batteries with Highly Enhanced Cyclic Stability

Abstract

Silicon (Si) has attracted tremendous attention as a high-capacity anode material for next generation Li-ion batteries (LIBs); unfortunately, it suffers from poor cyclic stability due to excessive volume expansion and reduced electrical conductivity after repeated cycles. To circumvent these issues, we propose that Si can be complexed with electrically conductive Ti2O3 to significantly enhance the reversible capacity and cyclic stability of Si-based anodes. We prepared a ternary nanocomposite of Si/Ti2O3/reduced graphene oxide (rGO) using mechanical blending and subsequent thermal reduction of the Si, TiO2 nanoparticles, and rGO nanosheets. As a result, the obtained ternary nanocomposite exhibited a specific capacity of 985 mAh/g and a Coulombic efficiency of 98.4% after 100 cycles at a current density of 100 mA/g. Furthermore, these ternary nanocomposite anodes exhibited outstanding rate capability characteristics, even with an increased current density of 10 A/g. This excellent electrochemical performance can be ascribed to the improved electron and ion transport provided by the Ti2O3 phase within the Si domains and the structurally reinforced conductive framework comprised of the rGO nanosheets. Therefore, it is expected that our approach can also be applied to other anode materials to enable large reversible capacity, excellent cyclic stability, and good rate capability for high-performance LIBs.

Graphene oxide: strategies for synthesis, reduction and frontier applications

“…15b and c shows galvanostatic cycling and the rate capability respectively. Besides various rGO based composites like (i) crumpled rGO/MoS 2 nanoflowers, 172 (ii) amorphous GeO x -coated rGO balls, 173 (iii) copper sulfide nanowires/rGO, 174 (iv) Si/Ti 2 O 3 /rGO, 175 (v) MnS hollow microspheres-rGO, 176 (vi) copper silicate hydrate hollow spheres-rGO 177 (vii) fluorine-doped tin oxide nanocrystal/rGO, 178 (viii) hollow nanobarrels of α-Fe 2 O 3 on rGO 179 and (ix) hierarchical rGO-Co 2 V 2 O 7 nanosheets 180 etc. shows an improved performance and stability as anode material for the lithium-ion batteries.…”

A Bioinspired Nanofibrous Titania/Silicon Composite as an Anode Material for Lithium‐Ion Batteries

“…Figure a displays the survey XPS spectrum of the composite; the Ti 2 p peak is observed in addition to peaks of silicon and oxygen, which indicates that the titania‐54.3 %‐silicon composite consists of titanium, silicon, and oxygen. A high‐resolution O 1 s XPS spectrum of the titania‐54.3 %‐silicon composite (Figure b) shows two peaks at 530.0 and 532.4 eV, which are attributed to Ti−O and Si−O, respectively . The high‐resolution spectrum of the Si 2 p region of the sample is shown in Figure c; the peaks located at 99.9 eV are indexed to metallic silicon, and the two other peaks located at 100.9 and 103.0 eV are indexed to silicon oxide (SiO x , x <2; and SiO 2 ) owing to the oxidation of silicon nanoparticles in air .…”

“…Therefore, volume changes of silicon nanoparticlesd uring repeated charge/discharge processes, when employed as anode materials for LIBs, could be largely suppressedo wing to the buffering effect of the titania coating layer on the silicon nanofiber surfaces, and enhanced electrochemical performance could be obtained. Moreover,t he original hierarchical network structures of the cellulose substance are maintained in the sample, whichp rovide enough space to accommodate the seriousv olume change of the anode upon cycling, and facilitate the electrode- [67] The high-resolution spectrumo ft he Si 2p region of the sample is shown in Figure 3c;the peaks located at 99.9 eV are indexed to metallic silicon, and the two other peaks located at 100.9 and 103.0 eV are indexed to silicon oxide (SiO x , x < 2; and SiO 2 )o wing to the oxidation of silicon nanoparticles in air. [23,26,68] This silicon oxide layer could serve as ab uffer layer for volumec hanges to the silicon nanocrystals upon charge/discharge cycles when the composite is employed as the anode of LIBs.…”

Recent Advances in Effective Reduction of Graphene Oxide for Highly Improved Performance Toward Electrochemical Energy Storage

“…[74] The thermal-reduced graphene-based materials were widely researched and applied to obtain low-defect graphene for energy storage devices. This led to excellent improvement in electrochemical performance of such devices as Li-ion batteries (LIBs), [55,[75][76][77][78][79][80][81][82][83][84] Li-air batteries, [85][86][87][88] Li-sulfur batteries (LSBs), [89] Na-ion batteries (SIBs), [81,90] Al-ion batteries (AlBs), [47][48][49][50] and SCs. [91] Zhang et al [83] used graphite oxide (GO) and triphenylphosphine (TPP) as carbon and phosphorus sources for synthesizing phosphorus-doped graphene (PG) by thermal annealing reduction (e.g., 1000°C).…”

“…The crumpled RGO and carbon fiber formed a dual continuous electronic transport network (Figure 2b), improving the electronic conductivity and the void spaces in crumpled RGO ensure the effective stress releasing and volume buffering, all of these resulted in a high reversible capacity (1225 mAh g À1 ) and excellent cycling stability (Figure 3c). Park et al [82] For preparing high-quality graphene, high-temperature annealing was necessary, which helped repair the defects in RGO to obtain well-structured graphene materials. Chen et al [55] firstly reported a high-quality RGO film with an electrical conductivity of up to 3112 S cm…”