Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Nat Commun. 2014 Jul 8;5:4105. doi: 10.1038/ncomms5105.
Nanostructured silicon is a promising anode material for high-performance lithium-ion batteries, yet scalable synthesis of such materials, and retaining good cycling stability in high loading electrode remain significant challenges. Here we combine in-situ transmission electron microscopy and continuum media mechanical calculations to demonstrate that large (>20 μm) mesoporous silicon sponge prepared by the anodization method can limit the particle volume expansion at full lithiation to ~30% and prevent pulverization in bulk silicon particles. The mesoporous silicon sponge can deliver a capacity of up to ~750 mAh g(-1) based on the total electrode weight with >80% capacity retention over 1,000 cycles. The first cycle irreversible capacity loss of pre-lithiated electrode is <5%. Bulk electrodes with an area-specific-capacity of ~1.5 mAh cm(-2) and ~92% capacity retention over 300 cycles are also demonstrated. The insight obtained from this work also provides guidance for the design of other materials that may experience large volume variation during operations.
纳米结构化硅是一种很有前途的高容量锂离子电池负极材料，但可扩展的此类材料的合成，以及在高负载电极中保持良好的循环稳定性仍然是重大挑战。在此，我们结合原位透射电子显微镜和连续介质力学计算证明，通过阳极氧化法制备的大尺寸 (>20 μm) 介孔硅海绵可以将完全嵌锂时的颗粒体积膨胀限制在30%，防止块状硅颗粒粉化。介孔硅海绵在总电极重量的基础上，可提供高达约 750 mAh g(-1) 的容量，且在 1000 次循环中保持超过 80%的容量。预锂化电极的首次循环不可逆容量损失<5%。此外，我们还展示了具有1.5 mAh cm(-2) 比容量和 300 次循环后~92%容量保持率的块状电极。这项工作获得的见解也为在操作过程中可能经历大体积变化的其他材料的设计提供了指导。
