High Rate Capability of SiOC Ceramic Aerogels with Tailored Porosity as Anode Materials for Li-ion Batteries
High Rate Capability of SiOC Ceramic Aerogels with Tailored Porosity as Anode Materials for Li-ion Batteries
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DOI：
10.1016/j.electacta.2015.01.088
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发表时间：
2015-03-01
影响因子：
6.6
通讯作者：
Riedel, R.
中科院分区：
文献类型：
--
作者：
Pradeep, V. S.;Ayana, D. G.;Riedel, R.
以线性聚硅氧烷与二乙烯基苯交联为原料，在Pt催化剂和丙酮溶剂的作用下，通过硅氢化反应合成了多孔富碳SiOC陶瓷气凝胶。得到的湿凝胶在溶剂中陈化，然后在超临界条件下用液态二氧化碳干燥。所得到的预陶瓷气凝胶在1000℃的可控氩气气氛下进行热解，形成所需的SiOC气凝胶。合成的SiOC陶瓷含有43 wt%的游离碳，游离碳被分离在无定形SiOC基体中。预陶瓷气凝胶的BET表面积高达230 m(2)g(-1)，在1000℃热解后仅略微减少到180m(2)g（-1）。电化学表征表明，在C （360 mA g(-1)）充电速率下，其比容量超过600 mAhg(-1)，并且具有良好的循环稳定性。在10C（3600毫安g(-1)）的速率下，可恢复高达200毫安g（-1）的比容量。从结构特征方面讨论了材料的优良性能。富碳陶瓷的多孔特性允许快速离子传输，并有助于适应结构变化，从而在重复锂化/脱锂过程中保持稳定的性能。(C) 2015 Elsevier Ltd.版权所有。
Porous carbon-rich SiOC ceramic aerogels have been synthesized from a linear polysiloxane cross-linked with divinylbenzene (DVB) via hydrosilylation reaction in presence of a Pt catalyst and acetone as a solvent. The obtained wet gels are aged in solvent followed by drying under supercritical conditions using liquid carbon dioxide. The resulting pre-ceramic aerogels are subjected to pyrolysis at 1000 degrees C under controlled argon atmosphere to form the desired SiOC aerogel. The synthesized SiOC ceramics contain 43 wt% of free carbon, which is segregated within amorphous SiOC matrix. The high BET surface area up to 230 m(2)g(-1) of preceramic aerogels is only slightly diminished to 180m(2)g(-1) after pyrolysis at 1000 degrees C. The electrochemical characterization reveals a high specific capacity of more than 600 mAhg(-1) at a charging rate of C (360 mA g(-1)) along with a good cycling stability. At a rate of 10C (3600 mA g(-1)) the specific capacities as high as 200 mAh g(-1) are recovered. The excellent properties of the materials are discussed with respect to their structural features. The porous nature of the carbon rich ceramics allows for fast ionic transport and helps to accommodate the structural changes which in turn allow a stable performance during repeated lithiation/delithiation. (C) 2015 Elsevier Ltd. All rights reserved.