Linzhen Lou, Xiangzhong Kong, Ting Zhu
Sep 10, 2018
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Influential Citations
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Science China Materials
Abstract
Niobium pentoxide (Nb2O5) has been extensively studied as anode materials for lithium ion batteries (LIBs) due to its good rate performance and safety advantages. However, the intrinsic low electronic conductivity has largely restricted its practical application. In this work, we report the construction of mesoporous T-Nb2O5 nanofibers by electrospinning followed by heat treatment in air. The interconnected mesoporous structure ensures a high surface area with easy electrolyte penetration. When used as anodes for LIBs, the mesoporous Nb2O5 electrode delivers a high reversible specific capacity of 238 mA h g−1 after 1,000 cycles at a current density of 1 A g−1 within a voltage range of 0.01–3.0 V. Even at a higher discharge cut-off voltage window of 1.0–3.0 V, it still possesses a high reversible capacity of 166 mA h g−1 after 200 cycles. Moreover, the porous Nb2O5 electrode also exhibits excellent rate capability. The enhanced electrochemical performances are attributed to the synergistic effects of porous nanofiber structure and unique crystal structure of T-Nb2O5, which has endowed this material a large electrode-electrolyte contact area with improved electronic conductivity.摘要五氧化二铌Nb2O5由于其良好的倍率性能和安全性, 作为锂离子电池负极材料被广泛研究. 但是其固有的低电子电导率在很大程度上限制了其电化学性能的发挥. 在本论文中, 我们通过静电纺丝和后续空气热处理构建了具有连续介孔结构的T-Nb2O5纳米纤维. 介孔结构彼此互连, 确保高表面积的同时也促进了电解液的渗透. 当用作锂离子电池负极时在电压窗口为0.01–3.0 V, 电流密度为1 A g−1的条件下, 循环1000圈后可逆比容量达到238 mA h g−1. 即使提高电压窗口到1.0–3.0 V, 在循环200圈后仍然有166 mA h g−1的可逆比容量. 此外, 电极材料还表现出优异的倍率性能. 多孔纳米纤维结构和T-Nb2O5独特晶体结构的协同效应, 增大了电极和电解质的接触面积, 改善了电子传导性, 从而使电化学性能得到提高.