Encapsulating MnO nanoparticles within foam-like carbon nanosheet matrix for fast and durable lithium storage
Encapsulating MnO nanoparticles within foam-like carbon nanosheet matrix for fast and durable lithium storage
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DOI：
10.1016/j.nanoen.2018.06.018
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发表时间：
2018-08
期刊：
影响因子：
17.6
通讯作者：
Yu-Chen Xiao;Chengyan Xu;Panpan Wang;H. Fang;Xueyin Sun;Feixiang Ma;Yi-Rong Pei;L. Zhen
中科院分区：
文献类型：
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作者：
Yu-Chen Xiao;Chengyan Xu;Panpan Wang;H. Fang;Xueyin Sun;Feixiang Ma;Yi-Rong Pei;L. Zhen
由于MnO的导电性较差，在锂化/脱锂过程中体积变化剧烈，因此锂离子电池用高功率密度长寿命MnO基负极材料仍是一个很大的挑战。本文中，为了同时实现高倍率容量和长循环寿命，MnO纳米颗粒通过受限相变过程被封装在泡沫状碳纳米片基质内。将聚多巴胺（PDA）包覆的ZnMnO 3纳米片在还原气氛中退火，MnO纳米颗粒及其周围的孔可以同步包覆在PDA衍生的碳纳米片中，形成具有球孔结构的MnO@C纳米片（MnO@C-BP）。由于Zn的蒸发而产生的内部空隙不仅可以容纳MnO纳米颗粒的巨大体积膨胀，而且还显著增大了比表面积，从而增强了赝电容储锂行为。此外，制备的厚度约为30 nm的片状MnO@C-BP可以为Li离子的快速扩散提供较短的路径，而连续的碳骨架促进了包覆的MnO纳米颗粒之间的电荷转移。由于这些优点，MnO@C-BP电极表现出优异的上级倍率性能（10 A g− 1时为514 mAh g −1，15 A g− 1时为383 mAh g−1）、出色的循环性能（2 A g−1下1000次循环后为1212 mAh g− 1，容量保持率为127%）以及0.1 A g−1时1178 mAh g − 1的高可逆容量。
Long-life MnO-based anodes with high power density for lithium ion batteries (LIBs) is still a great challenge due to the inferior electrical conductivity and drastic volume change of MnO during the lithiation/delithiation process. Herein, to achieve high rate capacity and long cycle life simultaneously, MnO nanoparticles were encapsulated within a foam-like carbon nanosheet matrix through a confined phase transition process. By annealing polydopamine (PDA) coated porous ZnMnO3nanosheets in a reducing atmosphere, MnO nanoparticles and surroundingin-situformed pores could be encapsulated in the PDA-derived carbon nanosheets synchronously, forming MnO@C nanosheets with ball-in-pore structure (MnO@C-BP). The internal voids originating from Zn evaporation can not only accommodate the huge volume expansion of MnO nanoparticles, but also significantly enlarge the specific surface area, leading to an enhanced pseudocapacitive Li-storage behavior. Moreover, the as-prepared sheet-shaped MnO@C-BP with thickness of about 30 nm can provide a short path for fast Li-ion diffusion, while the continuous carbon framework promotes the charge transfer between the encapsulated MnO nanoparticles. Because of these merits, MnO@C-BP electrode exhibits superior rate performance (514 mAh g−1at 10 A g−1, 383 mAh g−1at 15 A g−1), outstanding cycling performance (1212 mAh g−1after 1000 cycles at 2 A g−1, capacity retention of 127%), as well as a high reversible capacity of 1178 mAh g−1at 0.1 A g−1.