Silicon has much higher theoretical specific capacity than traditional graphite materials (3579 mAh g. Graphite: 372mAh g). However huge volumetric expansion (∼300%) of silicon seriously reduces its cyclic stability as anode in lithium-ion batteries. Though reduce the size of silicon based composites to nanoscale and tuning their porosity have been extensively studied, above strategies reduce the vibration density of the anode material unsurprisingly, which is not conducive to the advantage of high volumetric capacity anode. In this work, we design a unique graded silicon/carbon powder to maintain excellent energy storage performance at high vibration density. The composite of graded structure is constructed by first particles and second particles. The construction strategy is proved to be adoptable to achieve cost effective production of high performance silicon/carbon composite anode for development of advanced lithium-ion battery. Under the premise of industrial powder materials’ production technologies, a graded structure silicon/carbon composite with optimized synthetic condition shows high-reversible capacity of 827.4 mAh g at 200 mAh g (equal to 1464.5 Ah L) and it capacity remains at 715.0 mAh g after 800 cycles, with a capacity retention rate of 86.37%, which shows high cycle life.

中文翻译：

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一种梯度结构的高稳定性锂离子电池负极硅/碳复合粉末

硅具有比传统石墨材料高得多的理论比容量（3579 mAh g。石墨：372mAh g）。然而，硅的巨大体积膨胀（~300%）严重降低了其作为锂离子电池阳极的循环稳定性。尽管将硅基复合材料的尺寸减小到纳米级并调整其孔隙率已被广泛研究，但上述策略毫不奇怪地降低了负极材料的振动密度，这不利于发挥高容量负极的优势。在这项工作中，我们设计了一种独特的分级硅/碳粉末，以在高振动密度下保持优异的储能性能。分级结构的复合材料由第一颗粒和第二颗粒构成。事实证明，该构建策略可用于实现高性能硅/碳复合负极的成本有效生产，用于先进锂离子电池的开发。在工业粉末材料生产技术前提下，优化合成条件的梯度结构硅/碳复合材料在200 mAh g（相当于1464.5 Ah L）时表现出827.4 mAh g的高可逆容量，且容量保持在715.0 mAh g 800次循环后，容量保持率为86.37%，具有较高的循环寿命。