文章信息/Info

Title:

 Theoretical Calculation of an Intermediate�睺emperature H+/Li+ Conducting Electrolyte: Li14Zn(GeO4)4

作者:

 李翊寧; 魏濤

 濟(jì)南大學(xué)材料科學(xué)與工程學(xué)院

Author(s):

LI Yining;  WEI Tao

School of Material Science and Engineering, University of Jinan

關(guān)鍵詞:

 ; 固體氧化物燃料電池; 中低溫; 鋰離子傳導(dǎo); 質(zhì)子傳導(dǎo); Li+/H+交換機(jī)制

Keywords:

SOFCs;  low and intermediate temperature;  lithium ion conduct;  proton conduct;  mechanism of Li+/H+ exchange

DOI:

10.7502/j.issn.1674-3962.2017.09.07

文獻(xiàn)標(biāo)志碼:

A

摘要:

 固體氧化物燃料電池技術(shù)已歷經(jīng)近150年的發(fā)展史，但目前仍在努力步入市場(chǎng)化進(jìn)程中。過(guò)高的工作溫度\[氧化釔穩(wěn)定的氧化鋯（YSZ）基>800 ℃\]是限制其商業(yè)化推廣的主要原因，而研發(fā)低溫電解質(zhì)是降低其工作溫度的關(guān)鍵步驟。本研究通過(guò)第一性原理計(jì)算，報(bào)道了一種中低溫（200~600 ℃）基質(zhì)子傳輸電解質(zhì) Li14Zn(GeO4)4（LZG），建立了質(zhì)子在LZG內(nèi)傳輸分子動(dòng)力學(xué)模型。通過(guò)理論模擬，提出LZG為中低溫基鋰離子/質(zhì)子混合傳導(dǎo)電解質(zhì)， 質(zhì)子經(jīng)鋰離子/質(zhì)子交換機(jī)制，通過(guò)LZG內(nèi)存在的鋰離子空位而引入，并模擬了質(zhì)子與鋰離子在鋰離子空位的傳導(dǎo)機(jī)制。進(jìn)一步通過(guò)計(jì)算得出，質(zhì)子在LZG電解質(zhì)內(nèi)部以較高的離子遷移系數(shù)通過(guò)鋰離子空位進(jìn)行傳輸，并得到不同位點(diǎn)鋰離子與質(zhì)子遷移系數(shù)隨溫度變化曲線。最后給出不同離子在LZG電解質(zhì)內(nèi)遷移的電子態(tài)密度。本研究為新型電解質(zhì)的研發(fā)提供了理論指導(dǎo)，有益于將固體氧化物燃料電池（SOFCs）工作溫度從中高溫區(qū)（>600 ℃）向中低溫區(qū)（200~600 ℃）推進(jìn)。

Abstract:

SOFCs can convert chemical energy directly to electric energy efficiently with minimum emissions. Unfortunately, the existing SOFC technologies are still too expensive for commercial use due to the high operating temperature. A critical step toward low-cost SOFC technologies is to develop materials with high conductivity of oxygen ions or protons (O2- or H+) at lower temperatures. Li+ in some lithium ion conductors can be replaced by H+ through a reversible ion-exchange (even just in water solution), implying that it is possible to turn a lithium-ion conductor to a proton conductor by H+/Li+ exchange. Here we demonstrate that Li14Zn(GeO4)4 (LZG) exhibits not only lithium ion (for LIBs) but also protons (for SOFCs). In order to elucidate the mechanism of Li+ and H+ conduction in LSZG electrolyte, ab�瞚nitio molecular dynamics computation was used to investigate Li+ and H+ transport trajectories，the diffusivity and the electronic density of states (e-DOS) for each type of ions in Li14Zn(GeO4)4. And in turn, the obtained calculating data can guide future design for 200~600 ℃ based proton conductor.