Composite Li-ion battery cathodes formed via integration of carbon nanotubes or graphene nanoplatelets into chemical preintercalation synthesis of bilayered vanadium oxides
Composite Li-ion battery cathodes formed via integration of carbon nanotubes or graphene nanoplatelets into chemical preintercalation synthesis of bilayered vanadium oxides
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DOI：
10.1016/j.jallcom.2022.163929
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发表时间：
2022-01
影响因子：
6.2
通讯作者：
T. Averianov;E. Pomerantseva
中科院分区：
文献类型：
--
作者：
T. Averianov;E. Pomerantseva
双层钒氧化物是可充电电池的有吸引力的阴极材料。这些氧化物的扩展的层间空间和多样的化学性质产生高比容量。然而，由于这些材料的结构不稳定性和低电子电导率，容量保持率和倍率性能受到限制。将氧化物与一维和二维碳纳米颗粒组装可以产生高效的异质界面，这将增强电化学电荷存储特性。在这里，我们首次合成了具有碳纳米管（CNTs）和石墨烯纳米片（GNP）的双层氧化钒复合材料。纳米结构的碳最初通过在空气中快速氧化来官能化，以在碳表面上产生极性基团，产生fCNT和fGNP，并改善与水性化学预插层合成路线的相容性。选择锂预插层双层钒氧化物LVO（LVO = δ-LixV 2 O 5·nH 2 O）作为氧化还原活性组分，以促进Li+离子通过δ-V2 O 5的层间区域扩散。采用原位低温溶胶-凝胶法一步合成了LVO/fCNT和LVO/fGNP复合材料。与原始氧化物相比，我们观察到纳米复合材料中的容量保持率和速率性能的显著改善，这归因于通过与fCNT和fGNP集成而实现的改善的电子传输和异质界面稳定效应。这项工作说明了通过原位合成具有可控异质界面的纳米复合材料来增强材料功能的能力。
Bilayered vanadium oxides are attractive cathode materials for rechargeable batteries. The expanded interlayer space and versatile chemistries of these oxides yield high specific capacities. However, capacity retention and rate performance are limited due to structural instability and low electronic conductivity of these materials. Assembling the oxides with one- and two-dimensional carbon nanoparticles may produce highly efficient heterointerfaces that would enhance electrochemical charge storage properties. Here, we synthesize for the first time bilayered vanadium oxide composites with carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs). The nanostructured carbons were initially functionalized by flash oxidation in air to create polar groups on the carbon surface, producing fCNTs and fGNPs, and improve compatibility with an aqueous chemical preintercalation synthesis route. Lithium preintercalated bilayered vanadium oxide, LVO (LVO = δ-LixV2O5·nH2O), was selected as a redox active oxide component to facilitate Li+ion diffusion through the interlayer region of δ-V2O5. A one-step process was developed to synthesize LVO/fCNT and LVO/fGNP composites by an in situ low temperature sol-gel method. We observed marked improvements in capacity retention and rate performance in the nanocomposites as compared to the pristine oxide, which were attributed to both improved electron transport and heterointerface stabilization effect enabled by integration with fCNTs and fGNPs. This work illustrates the ability to enhance material functionality through the in situ synthesis of nanocomposites with controllable heterointerface.