Coupling between oxygen redox and cation migration explains unusual electrochemistry in lithium-rich layered oxides.
Coupling between oxygen redox and cation migration explains unusual electrochemistry in lithium-rich layered oxides.
复制标题
DOI：
10.1038/s41467-017-02041-x
复制
发表时间：
2017-12-12
影响因子：
16.6
通讯作者：
Chueh WC
中科院分区：
文献类型：
--
作者：
Gent WE;Lim K;Liang Y;Li Q;Barnes T;Ahn SJ;Stone KH;McIntire M;Hong J;Song JH;Li Y;Mehta A;Ermon S;Tyliszczak T;Kilcoyne D;Vine D;Park JH;Doo SK;Toney MF;Yang W;Prendergast D;Chueh WC
富锂层状过渡金属氧化物正极提供了高电位阴离子氧化还原的通道，从而有望实现锂离子电池的高能量密度。然而，阴离子氧化还原也与一些不利的电化学性质有关，如开路电压滞后。我们发现，在Li1.17-xNi0.21Co0.08Mn0.54O2中，这些特性是由阴离子氧化还原和阳离子迁移之间的强耦合引起的。我们结合各种x射线光谱，微观和结构探针表明，部分可逆的过渡金属迁移降低了体氧氧化还原对的电位bbb1v，导致循环过程中阴离子和阳离子氧化还原电位的重新排序。第一性原理计算表明，这是由于与过渡金属迁移相关的局部氧配位环境的剧烈变化。我们认为这一机制与稳定氧氧化还原偶有关，我们在光谱上观察到它可以持续500次充放电循环。采用阴离子氧化还原的锂离子电池电极具有高能量密度，但循环性能差。在这里，作者揭示了阴离子氧化还原的电压受到电池循环过程中发生的结构变化的强烈影响，这解释了其独特的电化学性质。
Lithium-rich layered transition metal oxide positive electrodes offer access to anion redox at high potentials, thereby promising high energy densities for lithium-ion batteries. However, anion redox is also associated with several unfavorable electrochemical properties, such as open-circuit voltage hysteresis. Here we reveal that in Li1.17–xNi0.21Co0.08Mn0.54O2, these properties arise from a strong coupling between anion redox and cation migration. We combine various X-ray spectroscopic, microscopic, and structural probes to show that partially reversible transition metal migration decreases the potential of the bulk oxygen redox couple by > 1 V, leading to a reordering in the anionic and cationic redox potentials during cycling. First principles calculations show that this is due to the drastic change in the local oxygen coordination environments associated with the transition metal migration. We propose that this mechanism is involved in stabilizing the oxygen redox couple, which we observe spectroscopically to persist for 500 charge/discharge cycles. Lithium ion battery electrodes employing anion redox exhibit high energy densities but suffer from poor cyclability. Here the authors reveal that the voltage of anion redox is strongly affected by structural changes that occur during battery cycling, explaining its unique electrochemical properties.
登录
查看更多内容
影响因子：
3.7
作者：
ABBATE, M;DEGROOT, FMF;TSUDA, N
通讯作者：
TSUDA, N
DOI：
10.1051/jp4:200300017
发表时间：
2003-03-01
期刊：
JOURNAL DE PHYSIQUE IV
影响因子：
--
作者：
Ade, H;Kilcoyne, ALD;Warwick, T
通讯作者：
Warwick, T
影响因子：
5.7
作者：
Chan, Maria K. Y.;Shirley, Eric L.;Fister, Tim T.
通讯作者：
Fister, Tim T.
影响因子：
3.7
作者：
Genevois, Cecile;Koga, Hideyuki;Weill, Francois
通讯作者：
Weill, Francois
影响因子：
8.6
作者：
Chen, Hungru;Islam, M. Saiful
通讯作者：
Islam, M. Saiful