A novel phosphatizing strategy to engineering CoO/Co 1.94 P@carbon polyhedron heterostructures for enhanced lithium-ion
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A novel phosphatizing strategy to engineering CoO/ Co1.94P@carbon polyhedron heterostructures for enhanced lithium-ion battery Zhuo Chen1 and Haibo Li1,* 1
Ningxia Key Laboratory of Photovoltaic Materials, Ningxia University, Yinchuan 750021, Ningxia, People’s Republic of China
Received: 2 June 2020
ABSTRACT
Accepted: 7 October 2020
High-performance anode enabled by heterostructured materials is very promising for lithium-ion battery. In this work, a facile one-pot method is developed to synthesize CoO/Co1.94P nanocrystals wrapped within carbon polyhedron (CoO/Co1.94P@CP) heterostructures. Benefiting from this novel structure, the lithiation/de-lithiation reaction is confined in CP, resulting in stable long cyclic performance. On the other hand, the massive CoO/Co1.94P nanocrystals are distributed uniformly in CP, which are beneficial to provide as much as active sites and highly exposed area for triggering the electrochemical reaction. Beyond that, the CP not only acts as a buffer layer to alleviate the volume expansion of CoO/Co1.94P but also improves the conductivity. As a result, the CoO/Co1.94P@CP anode exhibits the highly reversible capacity of 462.3 mAh g-1 at 0.2 A g-1 after 200 cycles and excellent rate capability (288.7 mAh g-1 at 1.0 A g-1). Moreover, the morphology characterization realizes that the microstructure of CoO/Co1.94P@CP maintains very well even after 200 charge/discharge cycles which again demonstrates the durability of the composite electrode.
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Introduction The lithium-ion batteries (LIBs) as one of the representative rechargeable batteries have been widely implemented in energy storage systems. Nevertheless, the current development of LIBs suffers from the low capacity which cannot catch up with the
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https://doi.org/10.1007/s10853-020-05428-2
increasing demand for high-power device, i.e. electric vehicle. Regarding the LIBs, the anode plays a significant role to improve the overall performance. Transition phosphides (TMPs) have been considered as good electrical conductors possessing high strength, hardness, thermal stability and chemical stability. When TMPs are proposed as anode for LIBs, it exhibits low redox potential and high theoretical
J Mater Sci
capacity (2596 mAh g-1) [1]. However, the drawbacks affiliating with TMPs are immense volume strain in the conversion reaction and low intrinsic conductivity, which undoubtedly hinder the chemical diffusion in TMPs’ crystal and lower the capacitance retaining after long cycles [2]. To address these issues, one of the most feasible strategies is to construct heterostructures by combing TMPs with carbon nanomaterials. In this case, the carbon nanostructure not only acts as a buffering layer to relieve the volume expansion of TMPs upon the cycling, but also enhances the conductivity of the whole electrode. Metal–organic frameworks (MOFs) are formed by self-assembling metal ions
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