Highly reversible Li/dissolved polysulfide batteries with binder-free carbon nanofiber electrodes
Highly reversible Li/dissolved polysulfide batteries with binder-free carbon nanofiber electrodes
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DOI：
10.1039/c3ta11958k
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发表时间：
2013-08
影响因子：
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通讯作者：
Chenxi Zu;Yongzhu Fu;A. Manthiram
中科院分区：
文献类型：
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作者：
Chenxi Zu;Yongzhu Fu;A. Manthiram
传统的锂硫电池容量衰减快，限制了其商业化应用。具有无粘合剂、交织、自立式碳电极的Li/溶解多硫化物电池在容量利用率和可逆性方面表现出出色的性能。为了进一步了解这个系统，我们在这里提出了一种无粘结剂的碳纤维（CNF）纸电极，具有纤维之间的大空隙，低制造成本，和高聚硫化物负载。CNF纸电极的3D交织结构允许高阶多硫化物（带电产物）和硫化锂（放电产物）之间的转变在受限环境内发生。在第一次放电后，在3D电极框架的大空隙内发现结晶Li 2S，避免了在阴极上形成致密的钝化层。坚固的多孔CNF纸电极具有上级电化学性能，在C/5倍率下循环80次后，可逆容量为1094 mA h g−1，库仑效率高于98%，硫负载量为1.7 mg cm−2。在5.1 mg cm−2的高得多的硫负载下，获得了10900 mA h g−1的稳定可逆容量，使这种电池配置具有实际应用的前景。
Conventional lithium–sulfur batteries suffer from rapid capacity fade which limits their commercialization applications. Li/dissolved polysulfide cells with binder-free, interwoven, self-standing carbon electrodes show outstanding performance in terms of capacity utilization and reversibility. To further understand this system, we present here a binder-free carbon nanofiber (CNF) paper electrode with large interspaces between fibers, low manufacturing cost, and high polysulfide loadings. The 3D interwoven structure of the CNF paper electrode allows transitions between high-order polysulfides (charged products) and lithium sulfide (discharged product) to occur within a confined environment. Crystalline Li2S is found within the large interspaces of the 3D electrode framework after the 1st discharge, avoiding the formation of dense passivation layers on the cathode. The robust porous CNF paper electrode leads to superior electrochemical performance with a reversible capacity of 1094 mA h g−1 after 80 cycles at a C/5 rate and Coulombic efficiencies above 98% with a sulfur loading of 1.7 mg cm−2. A stable reversible capacity of ∼900 mA h g−1 is obtained with a much higher sulfur loading of 5.1 mg cm−2, making this battery configuration promising for practical applications.