A Facile Pre-Lithiated Strategy towards High-Performance Li2Se-LiTiO2 Composite Cathode for Li-Se Batteries.

Yang Xia,Wenkui Zhang,Zhen Xiao,Chengwei Lu,Hui Huang,Xinping He,Guoguang Wang,Yongping Gan,Zheng Fang

doi:10.3390/nano12050815

Abstract

Conventional lithium-ion batteries with a limited energy density are unable to assume the responsibility of energy-structure innovation. Lithium-selenium (Li-Se) batteries are considered to be the next generation energy storage devices since Se cathodes have high volumetric energy density. However, the shuttle effect and volume expansion of Se cathodes severely restrict the commercialization of Li-Se batteries. Herein, a facile solid-phase synthesis method is successfully developed to fabricate novel pre-lithiated Li2Se-LiTiO2 composite cathode materials. Impressively, the rationally designed Li2Se-LiTiO2 composites demonstrate significantly enhanced electrochemical performance. On the one hand, the overpotential of Li2Se-LiTiO2 cathode extremely decreases from 2.93 V to 2.15 V. On the other hand, the specific discharge capacity of Li2Se-LiTiO2 cathode is two times higher than that of Li2Se. Such enhancement is mainly accounted to the emergence of oxygen vacancies during the conversion of Ti4+ into Ti3+, as well as the strong chemisorption of LiTiO2 particles for polyselenides. This facile pre-lithiated strategy underscores the potential importance of embedding Li into Se for boosting electrochemical performance of Se cathode, which is highly expected for high-performance Li-Se batteries to cover a wide range of practical applications.

Highlights

In recent years, the conventional lithium-ion batteries cannot meet the current development demand due to the limited energy density [1–9]
Sulfur cathode offers a high theoretical specific capacity of 1675 mA h g−1 when paired with lithium metal anode [10–12]
The development of Li-Se batteries still faces many problems, such as notorious shuttle effect and volume expansion in Li+ insert/extract processes, which cause the loss of active material and low Coulombic efficiency

Summary

Introduction

The conventional lithium-ion batteries cannot meet the current development demand due to the limited energy density [1–9]. In this respect, sulfur cathode offers a high theoretical specific capacity of 1675 mA h g−1 when paired with lithium metal anode [10–12]. TiO2 as secondary phase for Li-S/Se batteries is demonstrated to be an effective strategy on account of its strong chemisorption of lithium polysulfides/lithium polyselenides [14,28–31]. Is worth mentioning the pre-lithiation of Se chemical is a valid reagents, strategy which remains huge challenges in[32–34]. Li2Se-LiTiO2 composite the concise efficient synthesisinofFigure fully pre-lithiated. This polyselenides, rationally desuppressing the notorious shuttle effect This rationally designed signed Li2Se-LiTiO2 composite is a promising Se-based cathode for high-performance

Preparation

Materials Characterization

Electrochemical Measurements

Results and Discussion

Conclusions