Enhancing the long-term Na-storage cyclability of conversion-type iron selenide composite by construction of 3D inherited hyperbranched polymer buffering matrix  

作　　者：Hao Li Changchun Hu Yaping Xia Ting Li Daohong Zhang Fei Xu 

机构地区：[1]Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education&Hubei Key Laboratory of Catalysis and Materials Science,Hubei R&D Center of Hyperbranched Polymers Synthesis and Applications,School of Chemistry and Materials Science,South-Central University for Nationalities,Wuhan,430074,China [2]Key Laboratory of Hydraulic Machinery Transients,Ministry of Education,School of Power and Mechanical Engineering,Wuhan University,Wuhan,430072,China

出　　处：《Nano Research》2021年第11期3952-3960,共9页纳米研究（英文版）

基　　金：We gratefully acknowledge the financial support of Hubei Provincial Natural Science Foundation(Nos.2019CFB620 and 2019CFB452);Innovation group of Hubei Natural Science Foundation(No.2018CFA023);the Fundamental Research Funds for the Central Universities,South-Central University for Nationalities(No.CZY20022).

摘　　要：Electrochemical conversion reactions provide more selections for Na-storage materials, but the reaction suffers from low reversibility and poor cyclability. Introducing an electrochemically inactive component is a common strategy, but the effect is quite limited since it could not stabilize the structure during long-term cycling. In this study, a new approach is developed using an amino group-functioned hyperbranched polymer (AHP) as a template and electrode additive for the design of high-performance FeSe2-AHP composite with chemical interaction. The assembled FeSe2-AHP composite nanoneedles were prepared by the selenylation of FeS-AHP composite microflowers and entirely inherit the polymer network from the precursor. The amino groups of AHP in composite coordinate with iron cations to achieve uniform polymer dispersion in the composite, and maintain the molecular level mixed state during the long-term cycling. Moreover, the in-situ constructed uniform 3D elastic polymer network effectively accommodates volume expansion and alleviates nanoparticle aggregation during sodiation/de-sodiation. FeSe2-AHP composite provides a superior rate capability (584.8 mAh·g−1 at 20 A·g−1) and a remarkable cyclability with a capacity retention rate of 93.3% after 2,000 cycles. FeSe2-AHP composite shows a high pseudocapacitive behavior for the abundant nanometer interface established by AHP, enhancing the solid-state Na+ diffusion. The FeSe2-AHP anode is also compatible with Na3V2(PO4)3/C cathode in a full Na-ion battery, which provides a high-power performance (powering 51 LEDs). The work herein highlights an innovative and efficient strategy for conversion-type material design and demonstrates the function of chemical interaction of polymer additive in the enhancement of long-term cyclability for conversion electrode.

关 键 词：Na-ion batteries conversion materials hyperbranched polymer iron selenide chemical interaction 

分 类 号：TB33[一般工业技术—材料科学与工程]