Surface engineered polar CeO2-based cathode host materials for immobilizing lithium polysulfides in High-performance Li-S batteries
Surface engineered polar CeO2-based cathode host materials for immobilizing lithium polysulfides in High-performance Li-S batteries
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DOI：
10.1016/j.apsusc.2021.152237
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发表时间：
2022-04-01
影响因子：
6.7
通讯作者：
Wang, Ruigang
中科院分区：
文献类型：
--
作者：
Wei, Zhen;Li, Junhao;Wang, Ruigang
不同暴露晶面的CeO2纳米晶的颗粒形态是影响表面相关材料性能的关键因素。本文采用形状控制的方法合成了具有不同优选晶面的CeO2纳米晶体((110)/(100)/（11 11)的CeO2纳米棒、（100）的CeO2纳米立方体和（11 11）的CeO2纳米八面体），旨在研究极性CeO2作为阴极基质对多硫化物锂固定和组装的锂- s电池电化学性能的晶面效应。在从可溶长链多硫化物到不可溶短链Li2S/Li2S2的可逆电化学转化过程中，CeO2纳米棒暴露的(110)/(110)和缺陷的（111）晶面上形成了ce和Li-O键，并与CeO2主体形成了强化学键。在CeO2 nanorods@carbon布（CC）、CeO2 nanocubes@CC和CeO2 nanoctahedra@CC三种测试电极中，CeO2 nanorods@CC电极具有优异的电化学性能。然而，优先暴露（100）晶面的CeO2纳米立方体和优先暴露（11 11）晶面的CeO2纳米八面体并没有观察到这种对多硫化物的强化学相互作用。除了暴露的晶面因素外，CeO2纳米棒具有丰富的缺陷表面（即氧空位和Ce3+）也可能作为多硫化物的锚定位点，这有助于有效地固定多硫化物锂。由于具有上述优点，CeO2纳米棒被认为是长寿命高性能Li-S电池正极主体材料的优秀候选材料。
The particle morphology of CeO2 nanocrystals with different exposed crystal facets is a crucial factor influencing the surface-related materials performance. In this report, shape-controlled synthesis of CeO2 nanocrystals with various preferentially exposed crystal facets (CeO2 nanorods with (11 0)/(1 0 0)/(1 1 1), CeO2 nanocubes with (100) and CeO2 nanoctahedra with (1 1 1)) was conducted aiming to investigate the crystal plane effect of polar CeO2 as a cathode host on the immobilization of lithium polysulfides and electrochemical performance of the assembled Li-S batteries. The strong chemical bonding between lithium polysulfides and CeO2 host, including CeS and Li-O bonds formed on the exposed (11 0)/(1 0 0) and defected (111) crystal facets of CeO2 nanorods during reversible electrochemical conversion from soluble long-chain polysulfides to insoluble short-chain Li2S/Li2S2, results in superb diffusion restriction of lithium polysulfides towards Li anode and endows CeO2 nanorods@CC electrode with a superior electrochemical property among three tested electrodes of CeO2 nanorods@carbon cloth (CC), CeO2 nanocubes@CC, and CeO2 nanoctahedra@CC. However, such strong chemical interaction against polysulfides was not observed by CeO2 nanocubes with preferentially exposed (100) crystal planes and CeO2 nanoctahedra with preferentially exposed (1 1 1) crystal planes. In addition to the factor of the exposed crystal planes, CeO2 nanorods possess defect-rich surfaces (i.e., oxygen vacancies and Ce3+) also serving as possible polysulfides anchoring sites, which can contribute to effective immobilization of lithium polysulfides. Benefiting from the above-mentioned advantages, CeO2 nanorods are considered as an outstanding candidate of cathode host materials for long life and high-performance Li-S batteries.