High-Performance All-Solid-State Lithium–Sulfur Battery Enabled by a Mixed-Conductive Li2S Nanocomposite

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• 作者：Fudong Han ; Jie Yue ; Xiulin Fan ; Tao Gao ; Chao Luo ; Zhaohui Ma ; Liumin Suo ; Chunsheng Wang
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：July 13, 2016
• 年：2016
• 卷：16
• 期：7
• 页码：4521-4527
• 全文大小：424K
• 年卷期：0
• ISSN：1530-6992

文摘

All-solid-state lithium–sulfur batteries (ASSLSBs) using highly conductive sulfide-based solid electrolytes suffer from low sulfur utilization, poor cycle life, and low rate performance due to the huge volume change of the electrode and the poor electronic and ionic conductivities of S and Li₂S. The most promising approach to mitigate these challenges lies in the fabrication of a sulfur nanocomposite electrode consisting of a homogeneous distribution of nanosized active material, solid electrolyte, and carbon. Here, we reported a novel bottom-up method to synthesize such a nanocomposite by dissolving Li₂S as the active material, polyvinylpyrrolidone (PVP) as the carbon precursor, and Li₆PS₅Cl as the solid electrolyte in ethanol, followed by a coprecipitation and high-temperature carbonization process. Li₂S active material and Li₆PS₅Cl solid electrolyte with a particle size of ∼4 nm were uniformly confined in a nanoscale carbon matrix. The homogeneous nanocomposite electrode consisting of different nanoparticles with distinct properties of lithium storage capability, mechanical reinforcement, and ionic and electronic conductivities enabled a mechanical robust and mixed conductive (ionic and electronic conductive) sulfur electrode for ASSLSB. A large reversible capacity of 830 mAh/g (71% utilization of Li₂S) at 50 mA/g for 60 cycles with a high rate performance was achieved at room temperature even at a high loading of Li₂S (∼3.6 mg/cm²). This work provides a new strategy to design a mechanically robust, mixed conductive nanocomposite electrode for high-performance all-solid-state lithium sulfur batteries.