Electrostatic layer-by-layer self-assembly of 1D \u03b1-LiFeO2 with enhanced rate capability and cycling performance

Youzuo Hu,Xingquan Liu,Nuria Tapia-Ruiz

doi:10.1007/s10853-020-04581-y

Abstract

α-LiFeO2 is a promising cathode material for lithium-ion batteries due to its theoretically high specific capacity (282 mAh g−1), abundant nature, low cost of raw materials and environmental friendliness. However, the intrinsic sluggish kinetics and poor electronic conductivity of α-LiFeO2 prevent its practical use. In this work, we introduce a novel electrostatic layer-by-layer self-assembly method using PAH and PSS charged polyelectrolytes to grow in situ Ag nanoparticles on the surface of α-LiFeO2 nanorods to improve the electronic and ionic conductivity in this material. The experimental results show that such tailored design effectively improves the cycling stability and provides the material with a superior rate capability. The Ag-1D α-LiFeO2 material delivers a high discharge capacity of 162.6 mAh g−1 at 0.5 C and a capacity retention of 89.6% after 50 cycles. The excellent electrochemical behavior may be ascribed to synergistic effects which combine the use of Ag NPs, which provide with improved electronic conductivities, and the large specific surface areas given by the 1D morphology of the nanorods, providing increased lithium and electron conduction pathways.

Highlights

Rechargeable lithium-ion batteries (LIBs) have become the predominant power device for portable electronic products, electric and hybrid vehicles and smart grid applications [1, 2]
Layer-by-layer self-assembly (LBL) technology, which is a technique that lies on the deposition of alternating layers of oppositely charged materials is an efficient method that may provide with a uniform particle distribution [31, 32]
We demonstrate a novel, low-cost, simple and scalable method to prepare 1D a-LiFeO2 modified with Ag NPs based on an electrostatic layer-by-layer self-assembly process using poly(allylamine hydrochloride) (PAH) and poly(sodium 4-styrenesulfonate) (PSS) polyelectrolytes

Summary

Introduction

Explored. a-LiFeO2, with a disordered rock-salt structure, has been considered as a potential candidate to replace LiCoO2 due to its high theoretical capacity (282 mAh g-1), high elemental abundance, the low cost of the raw materials, environmental friendliness and safety during operation [4,5,6,7,8,9]. We demonstrate a novel, low-cost, simple and scalable method to prepare 1D a-LiFeO2 modified with Ag NPs based on an electrostatic layer-by-layer self-assembly process using PAH and PSS polyelectrolytes. As a result, enhanced ionic and electronic conductivities which enabled improved electrochemical performance in terms of cycling capability and rate performance were observed. This design strategy opens the pathway to the fabrication of new electrode designs with improved electrochemical properties. SEM (JEOL, JSM-6360LV) was performed using an accelerating voltage of 60 kV to determine the microstructure of the as-prepared a-LiFeO2 samples. The electrochemical performance of the 1D a-LiFeO2 samples and pristine material was tested by using CR2025 coin-type cells, which were assembled in an Ar-filled glove box. Cyclic voltammetry (CV) was conducted at a scan rate of 0.1 mV s-1 in the 1.5–4.8 V voltage range

Results and discussion

Conclusion

Compliance with ethical standards