"Nano-Pearl-String" TiNb2O7 as Anodes for Rechargeable Lithium Batteries
"Nano-Pearl-String" TiNb2O7 as Anodes for Rechargeable Lithium Batteries
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DOI：
10.1002/aenm.201200396
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发表时间：
2013-01-01
影响因子：
27.8
通讯作者：
Maier, Joachim
中科院分区：
文献类型：
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作者：
Tang, Kun;Mu, Xiaoke;Maier, Joachim
尽管在过去的几十年中已经实现了二次锂电池的显著增强，但是以较低的成本开发具有高能量和功率密度的用于电动/混合动力车辆的安全电池仍然是一个挑战。[1-3]就阳极而言，石墨仍然是商业电池中的主要阳极材料，在高功率下具有低动力学。[4，5]此外，由于电解质分解，在初始充电中在石墨上形成的钝化固体电解质界面（SEI）不可逆地消耗大量的锂。石墨中锂嵌入的电位接近于金属锂的事实有利于实现电池的高电压，但也导致在快速充电期间锂电镀的可能性。因此，必须关注锂枝晶的形成，这是在大型电动车辆中应用的巨大安全障碍。为了避免锂的沉积，阳极充电电位必须不那么负，在这方面，Li 4 Ti 5 O 12由于其相热力学结构和化学稳定性而成为一种有吸引力的替代物。然而，Li 4 Ti 5 O 12的理论容量相对较低（175 mAh/g），因为在1.5V下只有三个锂原子可插入尖晶石结构中。[6-最近，Goodenough等人提出TiNb 2 O 7作为Li 4 Ti 5 O 12的竞争者，具有更高的容量和不发生SEI形成的工作电压范围。[1]TiNb 2 O 7为层状单斜晶系，空间群为C2/m，Ti4+和Nb 5+均占据八面体共角共棱的位置。由于Ti4+和Nb 5+离子半径相近，可能存在反位无序。根据文献[12]，锂可以可逆地嵌入到TiNb 2 O 7原电池的（-I10）平面中并占据那里的间隙位置。[11根据5电子转移反应（Ti4 +/Ti 3+，Nb 5+/Nb 3+）计算，TiNb 2 O 7的理论容量为387.6mAh/g。以前的研究表明，在0.1 C下，在1-3 V的电压范围内，可逆容量为280 mAh/g，与Li 4 Ti 5 O 12相比已经有了显著的提高。[11]然而，由于TiNb 2 O 7作为阳极的可再充电锂离子电池的发展受到限制，
Even though significant enhancement of secondary lithium batteries has been achieved in the last decades, it remains a challenge to develop safe batteries for electric/hybrid vehicles with high energy and power density at lower cost.[1–3] As far as the anode is concerned, graphite, still the dominant anode material in commercial batteries, suffers from low kinetics at high power.[4, 5] In addition, the passivating solid electrolyte interphase (SEI) formed on graphite in the initial charge due to the electrolyte decomposition, consumes a significant amount of lithium irreversibly. The fact that the potential for lithium intercalation in graphite is close to metallic lithium is favorable for achieving a high voltage of the battery but also leads to the possibility of lithium plating during fast charge. Thus, lithium dendrite formation has to be concerned with which is an enormous safety hurdle for application in large electric vehicles. To avoid lithium plating, the anode charging potential must be less negative.In this regard, Li 4Ti 5O 12 appears to be an attractive alternative owing to phase thermodynamics structure and chemical stability. However, the theoretical capacity of Li 4Ti 5O 12 is relatively low (175 mAh/g) according to only three lithium atoms being insertable into the spinel structure at 1.5 V.[6–, 10] Recently, Goodenough et al. proposed TiNb 2O 7 as a competitor for Li 4Ti 5O 12 with a higher capacity and an operating voltage range in which SEI formation does not occur.[1] TiNb 2O 7 has a layered monoclinic structure in the space group C2/m, in which Ti 4+ and Nb 5+ both occupy octahedral sites sharing corners and edges. Anti-site disorder is probable owing to similar ionic radii of Ti 4+ and Nb 5+. According to ref [12], lithium can be reversibly inserted into the (–I10) plane of the TiNb 2O 7 primitive cell and occupying the interstitial site there.[11, 12] The theoretical capacity for TiNb 2O 7 is 387.6 mAh/g according to the 5 electron transfer reaction (Ti 4+/Ti 3+, Nb 5+/Nb 3+). Previous studies showed a reversible capacity of 280 mAh/g at 0.1 C in the voltage range of 1–3 V, already a marked enhancement compared to Li 4Ti 5O 12.[11] However, the development of rechargeable lithium ion batteries with TiNb 2O 7 as an anode has been limited due to