Fast-pulverization enabled simultaneous enhancement on cycling stability and rate capability of C@NiFe2O4 hierarchical fibrous bundle
Fast-pulverization enabled simultaneous enhancement on cycling stability and rate capability of C@NiFe2O4 hierarchical fibrous bundle
复制标题
快速粉碎可同时增强C@NiFe2O4分级纤维束的循环稳定性和倍率性能
DOI：
10.1016/j.jpowsour.2017.07.099
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发表时间：
2017-09-30
影响因子：
9.2
通讯作者：
Shi, Bi
中科院分区：
文献类型：
--
作者：
Chen, Zerui;Zhang, Yu;Shi, Bi
电化学研磨引起的粉化是NiFe2O4容量衰退的原因。增大电流密度通常会加速粉末化，使NiFe2O4的储锂性能变差。本研究表明，高电流诱导的快速粉碎可以作为一种有效的激活策略，快速同时增强高密度堆积在分层结构的纳米碳纤维链上的NiFe2O4纳米颗粒（NPs）的循环稳定性和速率能力。在高电流密度下，NiFe2O4 NPs的粉碎可以在几个循环中完成，暴露出更多的活性表面。在快速粉碎过程中，分层结构的碳纳米纤维链无论充电或放电，都能保持密集堆积的NiFe2O4 NPs的导电接触，这也通过多级结构适应有效地抑制了固体电解质间相（SEI）的重复断裂和生长，有利于薄而致密的SEI的快速形成。从而提供强大的粒子间连通性，增强循环稳定性和速率能力（例如加倍容量）。我们的研究结果表明，大电流诱导快速粉碎作为一种有效的激活策略，对于实现遭受电化学研磨效应的耐用电极材料具有潜在的重要性。(C) 2017年Elsevier B.V.出版
Electrochemical-grinding induced pulverization is the origin of capacity fading in NiFe2O4. Increasing current density normally accelerates the pulverization that deteriorates lithium storage properties of NiFe2O4. Here we show that the high current induced fast-pulverization can serve as an efficient activation strategy for quick and simultaneous enhancement on cycling stability and rate capability of NiFe2O4 nanoparticles (NPs) that are densely packed on the hierarchically structured carbon nanofiber strand. At a high current density, the pulverization of NiFe2O4 NPs can be accomplished in a few cycles exposing more active surface. During the fast-pulverization, the hierarchically structured carbon nano fiber strand maintains conductive contact for the densely packed NiFe2O4 NPs regardless of charge or discharge, which also effectively suppresses the repetitive breaks and growths of solid-electrolyte-interphase (SEI) via multiple-level structural adaption that favourites the quick formation of a thin and dense SEI, thus providing strong interparticle connectivity with enhancement on cycling stability and rate capability (e.g. doubled capacity). Our findings demonstrate the potential importance of high current induced fast-pulverization as an efficient activation strategy for achieving durable electrode materials suffering from electrochemical-grinding effects. (C) 2017 Published by Elsevier B.V.