Enhanced Cycling Stability through Erbium Doping of LiMn₂O₄ Cathode Material Synthesized by Sol-Gel Technique.

Hongyuan Zhao,Yashuang Wang,Bo Li,Jing Wang,Dongdong Li,Sridhar Komarneni,Li Dong,Xiuzhi Bai,Binbin Liu

doi:10.3390/ma11091558

Abstract

In this work, LiMn2−xErxO4 (x ≤ 0.05) samples were obtained by sol-gel processing with erbium nitrate as the erbium source. XRD measurements showed that the Er-doping had no substantial impact on the crystalline structure of the sample. The optimal LiMn1.97Er0.03O4 sample exhibited an intrinsic spinel structure and a narrow particle size distribution. The introduction of Er3+ ions reduced the content of Mn3+ ions, which seemed to efficiently suppress the Jahn–Teller distortion. Moreover, the decreased lattice parameters suggested that a more stable spinel structure was obtained, because the Er3+ ions in a ErO6 octahedra have stronger bonding energy (615 kJ/mol) than that of the Mn3+ ions in a MnO6 octahedra (402 kJ/mol). The present results suggest that the excellent cycling life of the optimal LiMn1.97Er0.03O4 sample is because of the inhibition of the Jahn-Teller distortion and the improvement of the structural stability. When cycled at 0.5 C, the optimal LiMn1.97Er0.03O4 sample exhibited a high initial capacity of 130.2 mAh g−1 with an excellent retention of 95.2% after 100 cycles. More significantly, this sample showed 83.1 mAh g−1 at 10 C, while the undoped sample showed a much lower capacity. Additionally, when cycled at 55 °C, a satisfactory retention of 91.4% could be achieved at 0.5 C after 100 cycles with a first reversible capacity of 130.1 mAh g−1.

Highlights

Many people have realized the importance of green travel, which is very useful for reducing environmental pollution and protecting human health
The LiAlx Mn2−x O4 samples synthesized by a solution combustion technique showed better cycling life as a result of the reduced Jahn-Teller distortion by Al-doping [35]. These results indicated that the cycling life of LiMn2 O4 could be improved by doping with other cations
These results suggest that the high-rate of LiMn2 O4ofcan be enhance by doping retention of 93.9%

Summary

Introduction

Many people have realized the importance of green travel, which is very useful for reducing environmental pollution and protecting human health. It is generally known that there are four major classes of mature cathode materials, namely LiCoO2 [9,10], LiFePO4 [11,12], LiNi1−x−y Cox My O2 (M = Mn, Al) [13,14], and LiMn2 O4 [15,16], for batteries. Among these materials, LiMn2 O4 shows many virtues such as mature production. There is a tremendous need to optimize this material for better performance

Methods

Discussion

Conclusion