Defective Ti2Nb10O27.1: an advanced anode material for lithium-ion batteries.
Defective Ti2Nb10O27.1: an advanced anode material for lithium-ion batteries.
复制标题
有缺陷的Ti2Nb10O27.1：一种先进的锂离子电池负极材料
DOI：
10.1038/srep17836
复制
发表时间：
2015-12-03
影响因子：
4.6
通讯作者：
Lin S
中科院分区：
文献类型：
--
作者：
Lin C;Yu S;Zhao H;Wu S;Wang G;Yu L;Li Y;Zhu ZZ;Li J;Lin S
为探索大容量、高倍率性能的电动汽车锂离子电池负极材料，在氩气气氛下，采用固相反应法制备了缺陷型Ti 2Nb 10 O27. 1正极材料。X射线衍射结合Rietveld精修表明，Ti_2Nb_（10）O_（27.1）具有与化学计量比的Ti_2Nb_（10）O_（29）相同的晶体结构（A_2/m空间群的Wadsley-Roth剪切结构），但晶格常数较大，O_2-空位（相对于所有O_2-离子）为6.6%。Ti2Nb10O27.1的电子电导率和Li+离子扩散系数分别比Ti 2Nb 10 O29大6个数量级和约2.5倍。第一性原理计算表明，Ti_2Nb_（10）O_（29-x）中杂质带的形成及其导电特性是导致电子电导率显著提高的主要原因。由于电子和离子电导率的改善，Ti 2Nb 10 O 27.1不仅表现出329 mAh g-1的大的初始放电容量和286 mAh g-1的充电容量在0.1 C，而且还具有优异的倍率性能和循环性能。在5C下，其充电容量保持在180 mAh g-1，100次循环后容量保持率高达91.0%，而Ti_2Nb_（10）O_（29）的容量保持率仅为90 mAh g-1和74.7%。
To explore anode materials with large capacities and high rate performances for the lithium-ion batteries of electric vehicles, defective Ti2Nb10O27.1has been prepared through a facile solid-state reaction in argon. X-ray diffractions combined with Rietveld refinements indicate that Ti2Nb10O27.1has the same crystal structure with stoichiometric Ti2Nb10O29(Wadsley-Roth shear structure withA2/mspace group) but larger lattice parameters and 6.6% O2–vacancies (vs.all O2–ions). The electronic conductivity and Li+ion diffusion coefficient of Ti2Nb10O27.1are at least six orders of magnitude and ~2.5 times larger than those of Ti2Nb10O29, respectively. First-principles calculations reveal that the significantly enhanced electronic conductivity is attributed to the formation of impurity bands in Ti2Nb10O29–xand its conductor characteristic. As a result of the improvements in the electronic and ionic conductivities, Ti2Nb10O27.1exhibits not only a large initial discharge capacity of 329 mAh g–1and charge capacity of 286 mAh g–1at 0.1 C but also an outstanding rate performance and cyclability. At 5 C, its charge capacity remains 180 mAh g–1with large capacity retention of 91.0% after 100 cycles, whereas those of Ti2Nb10O29are only 90 mAh g–1and 74.7%.