Dendrite-Free Nanostructured Anode: Entrapment of Lithium in a 3D Fibrous Matrix for Ultra-Stable Lithium-Sulfur Batteries
Dendrite-Free Nanostructured Anode: Entrapment of Lithium in a 3D Fibrous Matrix for Ultra-Stable Lithium-Sulfur Batteries
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无枝晶纳米结构阳极：将锂包埋在 3D 纤维基质中，用于超稳定的锂硫电池
DOI：
10.1002/smll.201401837
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发表时间：
2014-11-12
期刊：
影响因子：
13.3
通讯作者：
Zhang, Qiang
中科院分区：
文献类型：
--
作者：
Cheng, Xin-Bing;Peng, Hong-Jie;Zhang, Qiang
程新兵，彭洪杰，黄佳琪，魏飞，张强*薄膜具有离子导电性和电绝缘性，随着枝晶的形成电阻变大。在SEI形成过程中，裸锂不断被消耗，降低了整个电池的循环效率。另一方面，枝晶锂具有比平板锂更高的反应活性。在去锂化过程中，锂枝晶的底部倾向于首先失去锂，在局部区域迅速溶解，并与阳极分离，[13]导致“死锂”的形成，与集流器分离，不贡献容量。这也降低了金属锂电池中锂阳极的效率和稳定性。锂表面层的组成、性质和稳定性以及再沉积锂的形貌是决定金属锂电池电池性能的关键因素。如果能提高电解液与锂电极界面的稳定性和均匀性，则可相应延缓枝晶的形成和生长各种电解质添加剂（如二氧化碳/二氧化硫、氟化氢、2-甲基呋喃等）[12]通常比溶剂和盐具有更高的还原电压来增强Li金属上的界面。它们与锂阳极快速反应，形成致密的保护性界面，进一步减少了锂与电解质之间严重的寄生反应。近年来，利用还原电位低于标准Li/Li+的低浓度铯（Cs）或铷（Rb）离子，通过在Li突周围形成带正电荷的自愈静电屏蔽来抑制枝晶的生长，其中Cs或Rb阳离子由于还原电位较低，在Li沉积过程中不能被消耗，即使经过长期循环也能保持有效除了原位形成的SEI薄膜保护锂阳极外，还提出了通过物理约束来阻止枝晶渗透的非原位涂覆聚合物层离子-液体-纳米颗粒杂化电解质[16]和纳米多孔聚合物-陶瓷复合电解质[17]具有电化学稳定性、力学性能和促进稳定锂电沉积的能力，可有效抑制循环锂阳极上枝晶的形成。因此，上述策略有效地调节了锂枝晶在液体电解质中的生长行为。如果用聚合物电解质(如聚（环氧乙烷）、[2,18]凝胶聚合物电解质[19]、全固态电解质（如氮掺杂磷酸锂离子膜、[20]陶瓷玻璃、[21]和硫代磷酸锂基剪切模量大、高的超离子导体[22]）代替有机电解质
Xin-Bing Cheng, Hong-Jie Peng, Jia-Qi Huang, Fei Wei, and Qiang Zhang* film is ionic conductive and electrical insulative, the resistance becomes larger as dendrites formed. During SEI formation, bare Li is continuously consumed, which decreases the cyclic efficiency of the whole cell. On the other hand, the dendrited Li possesses higher reactivity than plate Li. During the de-lithiation, the bottom of the Li dendrites prefers to lose Li first, rapidly dissolves at the local region, and breaks away from the anode,[13] leading to the formation of “dead Li” that is detached from the current collector and contributes no capacity. This also lowers the efficiency and stability of lithium anode in metallic Li batteries. The composition, properties, and stability of the surface layer on Li, as well as the morphology of re-deposited Li are key factors that determine the cell performance of metallic Li batteries. If the stability and uniformity of the interfaces between electrolytes and Li electrode can be improved, the dendrite formation and growth would be retarded accordingly.[14] Various electrolyte additives (such as carbon dioxide/sulfur dioxide, hydrogen fluoride, 2-methylfuran, etc.)[12] with higher reduction voltages than solvents and salts are often employed to reinforce the interfaces on the Li metal. They react with Li anode quickly, form a dense and protective interphase, which further minimizes severe parasitic reactions between Li and electrolytes. Recently, low concentrations of cesium (Cs) or rubidium (Rb) ions with lower reduction potential than standard Li/Li+ were employed to restrain the dendrite growth via self-healing electrostatic shield with positive charge formed around the Li protuberances to prevent further growth of dendrite, in which Cs or Rb cations cannot be consumed during Li deposition due to the lower reduction potential and thus remain effective even after long-term cycling.[11] Except for in-situ formed SEI films to protect Li anode, ex-situ coated polymer layers have been proposed to block dendrite penetration by physical confinement.[15] The ionic-liquid-nanoparticle hybrid electrolytes [16] and nanoporous polymer-ceramic composite electrolytes [17] with electrochemical stability, mechanical properties, and ability to promote stable Li electrodeposition are efficient in suppressing dendrite formation on cycled Li anodes. Thus, the growth behavior of Li dendrites has been effectively tuned by aforementioned strategies in liquid electrolytes. If organic electrolytes are replaced by polymer electrolytes (eg poly (ethylene oxide),[2, 18] gel polymer electrolytes [19], allsolid-state electrolytes (eg nitrogen-doped Li-ion phosphate film,[20] ceramic glass,[21] and lithium thiophosphate based superionic conductors [22] with large shearing modulus, high