Porosity- and Graphitization-Controlled Fabrication of Nanoporous Silicon@Carbon for Lithium Storage and Its Conjugation with MXene for Lithium-Metal Anode
Porosity- and Graphitization-Controlled Fabrication of Nanoporous Silicon@Carbon for Lithium Storage and Its Conjugation with MXene for Lithium-Metal Anode
复制标题
孔隙率和石墨化控制的锂存储用纳米多孔硅@碳的制备及其与 MXene 的共轭锂金属阳极
DOI：
10.1002/adfm.201908721
复制
发表时间：
2019-12-20
影响因子：
19
通讯作者：
Qian, Yitai
中科院分区：
文献类型：
--
作者：
An, Yongling;Tian, Yuan;Qian, Yitai
硅和金属锂是高能量密度锂电池最理想的负极材料。然而，大的体积膨胀和较低的电导率限制了硅阳极的商业化，而枝晶的形成限制了锂金属阳极的应用。本文从工业合金和二氧化碳中制备了均匀的纳米多孔Si@C(NPSI@C)，并将其作为锂离子电池的稳定负极进行了测试。通过调整反应条件，可以控制硅的孔隙率以及碳层的石墨化程度和厚度。合理设计NPSI@C的孔隙率和碳层，可以在不破坏碳层和破坏固体电解质界面层的情况下，提高硅的电子导电性和缓冲体积变化。优化后的NPSI@C负极表现出稳定的循环性能，在2000次循环中，5Ag(-1)下的容量衰减率为0.00685%。通过定量动力学分析对储能机理进行了探讨，证明储能机理为电容-电池二元模型。此外，结合MXene和NPSI@C设计了一种新的2D/3D结构，NPSI@C作为亲锂成核种子，可以诱导均匀的锂沉积和缓冲体积膨胀，这一点通过对铜箔和MXene@NPSI@C上锂金属沉积形态的探索得到了证实。通过Li(Ni0.8Co0.1Mn0.1)O-2阴极的全电池测试，评估了NPSI@C和MXene@NPSI@C的实际应用潜力。
Silicon (Si) and lithium metal are the most favorable anodes for high-energy-density lithium-based batteries. However, large volume expansion and low electrical conductivity restrict commercialization of Si anodes, while dendrite formation prohibits the applications of lithium-metal anodes. Here, uniform nanoporous Si@carbon (NPSi@C) from commercial alloy and CO2 is fabricated and tested as a stable anode for lithium-ion batteries (LIBs). The porosity of Si as well as graphitization degree and thickness of the carbon layer can be controlled by adjusting reaction conditions. The rationally designed porosity and carbon layer of NPSi@C can improve electronic conductivity and buffer volume change of Si without destroying the carbon layer or disrupting the solid electrolyte interface layer. The optimized NPSi@C anode shows a stable cyclability with 0.00685% capacity decay per cycle at 5 A g(-1) over 2000 cycles for LIBs. The energy storage mechanism is explored by quantitative kinetics analysis and proven to be a capacitance-battery dual model. Moreover, a novel 2D/3D structure is designed by combining MXene and NPSi@C. As lithiophilic nucleation seeds, NPSi@C can induce uniform Li deposition with buffered volume expansion, which is proven by exploring Li-metal deposition morphology on Cu foil and MXene@NPSi@C. The practical potential application of NPSi@C and MXene@NPSi@C is evaluated by full cell tests with a Li(Ni0.8Co0.1Mn0.1)O-2 cathode.