Ultrafast and Stable Li-(De)intercalation in a Large Single Crystal H-Nb2O5 Anode via Optimizing the Homogeneity of Electron and Ion Transport
Ultrafast and Stable Li-(De)intercalation in a Large Single Crystal H-Nb2O5 Anode via Optimizing the Homogeneity of Electron and Ion Transport
复制标题
通过优化电子和离子传输的均匀性，在大型单晶 H-Nb2O5 阳极中实现超快稳定的锂（脱）嵌
DOI：
10.1002/adma.202001001
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发表时间：
2020
影响因子：
29.4
通讯作者：
Li Xianfeng
中科院分区：
文献类型：
--
作者：
Song Zihan;Li Hui;Liu Wei;Zhang Hongzhang;Yan Jingwang;Tang Yongfu;Huang Jianyu;Zhang Huamin;Li Xianfeng
探索具有快速、安全、稳定锂离子插入的负极材料对开发下一代锂离子电池具有重要意义。单斜型氢型五氧化铌具有优异的内在快速Li - de嵌入动力学、高比容量和安全性；然而，由于整个晶体的相变不同步，其实际速率能力和循环稳定性仍然有限。本文通过均匀化晶体周围的电子和锂离子电导率来解决这个问题。在微米单晶H - nb2o5粒子上引入非晶N掺杂碳层，以优化电子和Li离子输运的均匀性。结果表明，制备的H‐nb2o5具有高可逆容量（50 mA g−1时可达250 mAh g−1），前所未有的高倍率性能（16.0 a g−1时≈120 mAh g−1）和优异的循环稳定性（1000次循环后≈170 mAh g−1时2.0 a g−1），这是迄今为止H‐nb2o5材料中性能最高的。通过透射电镜和X射线衍射进一步证实了其内在原理。从而为锂离子电池电极材料的进一步发展提供了新的见解。
Exploring anode materials with fast, safe, and stable Li‐(de)intercalation is of great significance for developing next‐generation lithium‐ion batteries. Monoclinic H‐type niobium pentoxide possesses outstanding intrinsic fast Li‐(de)intercalation kinetics, high specific capacity, and safety; however, its practical rate capability and cycling stability are still limited, ascribed to the asynchronism of phase change throughout the crystals. Herein this problem is addressed by homogenizing the electron and Li‐ion conductivity surrounding the crystals. An amorphous N‐doped carbon layer is introduced on the micrometer single‐crystal H‐Nb2O5particle to optimize the homogeneity of electron and Li‐ion transport. As a result, the as‐prepared H‐Nb2O5exhibits high reversible capacity (>250 mAh g−1at 50 mA g−1), unprecedented high‐rate performance (≈120 mAh g−1at 16.0 A g−1) and excellent cycling stability (≈170 mAh g−1at 2.0 A g−1after 1000 cycles), which is by far the highest performance among the H‐Nb2O5materials. The inherent principle is further confirmed via operando transmission electron microscopy and X‐ray diffraction. A novel insight into the further development of electrode materials forlithium‐ion batteries is thus provided.