Largely Increased Lithium Storage Ability of Mangnese Oxide through a Continuous Electronic Structure Modulation and Elevated Capacitive Contribution,ACS Sustainable Chemistry & Engineering

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Largely Increased Lithium Storage Ability of Mangnese Oxide through a Continuous Electronic Structure Modulation and Elevated Capacitive Contribution
ACS Sustainable Chemistry & Engineering ( IF 7.1 ) Pub Date : 2018-12-05 00:00:00 , DOI: 10.1021/acssuschemeng.8b04258
Shifei Huang ₁ , Da Tie ₁ , Miao Wang ₁ , Bo Wang ₁ , Peng Jia ₁ , Qingjie Wang ₂ , Guoliang Chang ₃ , Jiujun Zhang ₃ , Yufeng Zhao _{1,

2}

Affiliation

An ultrathin MnO₂ sheet assembled three-dimensional flower microsphere grown on nitrogen-doped graphene is synthesized through a hydrothermal treatment method. When tested as an anode in a lithium-ion battery, the obtained material exhibits a high discharge capacity of 993 mAh g^–1 in the second cycle at 0.1 A g^–1, which goes up to 2243 mAh g^–1 gradually after 135 charge/discharge cycles. This phenomenon turns out to be related to the deep coupling between nitrogen-doped graphene and MnO₂ caused by morphology evolution of the composite upon cycling. Also, kinetics analysis reveals the elevated capacitive contribution after cyclic reaction, indicating the ever enhanced phase interface charge storage mechanism associated with the morphology evolution. Otherwise, the first-principles calculations also indicate the electronic structure of MnO₂ can be efficiently modulated by coupling with a conductive graphene substrate, through a covalent C–Mn or N–Mn bond; thus, the deep coupling between nitrogen-doped graphene and MnO₂ during the charge/discharge process will gradually promote an elevated charge mobility and charge storage ability. This work provides a novel insight from the atomic scale to understand the capacity rising obsession for transition metal oxides, both theoretically and experimentally.

中文翻译：

通过连续的电子结构调制和高电容贡献，大大提高了氧化锰的锂存储能力

通过水热处理法合成了在氮掺杂石墨烯上生长的超薄MnO ₂片状组装三维花微球。当作为锂离子电池的阳极进行测试时，所获得的材料在0.1 A g ^–1的第二个循环中显示出993 mAh g ^–1的高放电容量，经过135次充电后逐渐达到2243 mAh g ^–1 /放电周期。事实证明，这种现象与氮掺杂石墨烯和MnO ₂之间的深耦合有关。由复合物在循环时的形态演变引起的。同样，动力学分析揭示了循环反应后升高的电容性贡献，表明与形态演化相关的相界面电荷存储机制不断增强。否则，第一性原理计算还表明，MnO ₂的电子结构可以通过共价C-Mn或N-Mn键与导电石墨烯基体偶联而得到有效调节。因此，氮掺杂石墨烯与MnO ₂之间的深耦合在充电/放电过程中，将逐渐促进电荷迁移率和电荷存储能力的提高。这项工作从原子尺度上提供了新颖的见解，以从理论上和实验上理解过渡金属氧化物的容量上升趋势。

更新日期：2018-12-05

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