Designing Uniformly Layered FeTiO3 Assemblies Consisting of Fine Nanoparticles Enabling High-Performance Quasi-Solid-State Sodium-Ion Capacitors.

Lei Liu,Shijia Zhang,Yi Zheng,Hongsen Li,Ling Huang,Zhengqiang Hu,Xiangjun Lu,Zhongchen Zhao

doi:10.3389/fchem.2020.00371

Lei Liu, Shijia Zhang + Show 6 more

Open Access

https://doi.org/10.3389/fchem.2020.00371

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Abstract

Sodium-ion capacitors (NICs) that have integrated the dual advantages of the high output of supercapacitors and the high energy density of batteries have stimulated growing attention for the next generation of practical electrochemical energy storage devices. The last years have seen the unprecedentedly rapid emergence of ilmenite materials, which present great promise in the realm of energy storage. However, NICs based on ilmenite materials have been scarcely researched so far. Instead, most of the current devices explored applied flammable liquid electrolytes, leading to a concern about unexpected leakage and potential safety problems. Herein, a quasi-solid-state NIC is constructed by employing the prepared uniformly layered FeTiO3 assemblies consisting of fine nanoparticles as anode and sodium ion conducting gel polymer as electrolyte. The resulting device delivers a high-energy-high-power density (79.8 Wh kg−1, 6,750 W kg−1), putting it among the state-of-the-art NICs. Furthermore, the assembled quasi-solid-state device also manifests long-term cycling stability over 2,000 cycles with a capacity retention ~80%. The uniformly layered FeTiO3 has great potential in developing low-cost and high-performance electrodes for the next generation of sodium and other metal ions-based energy storage devices.

Highlights

Electrochemical energy storage devices capable of high power and energy density are gaining widespread attention on account of the great industrial demands in the portable electronic, electrical vehicles, and smart grid markets (Dunn et al, 2011; El-Kady et al, 2015; Lu et al, 2017)
The precursor was further converted into uniformly-layered FeTiO3 assembles with high crystallinity through calcination at 600◦C for 10 h in Ar atmosphere
The unique multilayer structure, homogeneity, and monodispersed of the synthesized layered FeTiO3 assembles (L-FTO) and precursor are shown in Figure 1, Figure S1, respectively

Summary

Introduction

Electrochemical energy storage devices capable of high power and energy density are gaining widespread attention on account of the great industrial demands in the portable electronic, electrical vehicles, and smart grid markets (Dunn et al, 2011; El-Kady et al, 2015; Lu et al, 2017). By means of a facile solvothermal reaction coupled with further calcination, we successfully designed and synthesized the uniformly layered FeTiO3 assembles (L-FTO), which was further served as the superior anode material for quasi-solid-state NICs. A kind of Na+ conducting gel polymer employing the P(VDF-HFP) membrane as the matrix was used as the electrolyte.

Results

Conclusion