Strong interplay between dopant and SnO2 in amorphous transparent (Sn, Nb)O-2 anode with high conductivity in electrochemical cycling
Strong interplay between dopant and SnO2 in amorphous transparent (Sn, Nb)O-2 anode with high conductivity in electrochemical cycling
复制标题
在电化学循环中具有高电导率的非晶透明 (Sn, Nb)O-2 阳极中掺杂剂与 SnO2 之间的强相互作用
DOI：
10.1016/j.jallcom.2017.12.021
复制
发表时间：
2018
影响因子：
6.2
通讯作者：
Shao Guosheng
中科院分区：
文献类型：
--
作者：
Zhang Shilin;Zhang Jinhua;Cao Guoqin;Wang Qian;Hu Junhua;Zhang Peng;Shao Guosheng
SnO 2阳极结构完整性的丧失和固有的导电性差是容量衰减的主要原因。研究证实了循环过程中β → α的严重相分离与容量衰减密切相关。为了解决这些问题，制备了具有高导电性的非晶透明（Sn，Nb）O2。具有全氧化态的Nb掺杂剂通过将其载流子浓度提高到3.02 × 10− 20 cm −3的水平而赋予SnO 2 211.42 S/cm的高电导率。在20 C（约30 A g-1）的倍率下，具有6at. NTO 6样品的比容量在速率恢复到0.1C时基本恢复到原始容量，90次循环后仍保持在986 mA h g− 1。在电化学循环过程中，Nb掺杂剂与主体SnO 2的强相互作用被验证。Nb的最佳含量为6at.%可抑制β-锡向α -锡的同素异形转变，循环200次仍保持982.7 mA h g-1的容量。同时，Nb掺杂的非晶态SnO 2晶化为金红石结构，有利于在电化学反应过程中释放应力。循环性能的改善与Nb+5价态的持久性密切相关，这将有助于保持SnO 2基质材料的高电导率。结果，NTO 6在200次循环内保持无裂纹，具有低电阻抗。
The loss of structure integrity and intrinsic poor conductivity of SnO2anode are regarded as the main origination of capacity decay. In this work, a serious phase separation of β → α during cycling was confirmed and related with the capacity decaying closely. To address these challenges, an amorphous transparent (Sn, Nb)O2with high conductivity was fabricated. The Nb dopant with a full oxidation state endows SnO2with high conductivity of 211.42 S/cm by increasing its carrier concentration to the level of 3.02 × 10−20cm−3. At a rate of 20C (about 30 A g−1), discharge capacity of (Sn, Nb)O2with Nb content of 6 at. % can still remain 658 mA h g−1and the specific capacity of NTO6 sample nearly got back to its original capacity when the rate returned back to 0.1C, maintaining at 986 mA h g−1after 90 cycles. During the electrochemical cycling, the strong interplay of Nb dopant with host SnO2was verified. Nb with an optimized content of 6 at.% can suppress the allotropy transformation from β to α - tin and sustain a capacity of 982.7 mA h g−1till to 200 cycles. At the same time, Nb doped amorphous SnO2crystallized into rutile structure, which would help to release stress during electrochemical reaction. The improved cycling performance is closely related with a persistence of Nb+5valence, which will help to keep high conductivity of the host SnO2materials. As a result, NTO6 remained crack-free, with a low electrical impedance within 200 cycles.