Effects of Cr[sup.3+] Doping on Spinel LiMn[sub.2]O[sub.4] Morphology and Electrochemical Performance

• Published in: International journal of molecular sciences 2024-12, Vol.25 (24)
• Main Authors: Pei, Zhengqing, Wang, Jiawei, Wang, Haifeng, Zheng, Kexin, Wang, Qian, Zhou, Xinjie, Ma, Dehua, Lu, Ju
• Format: Article
• Language: English
• Subjects: Batteries; Crystals; Electrochemistry; Spinel group; Structure
• ISSN: 1422-0067
• DOI: 10.3390/ijms252413270

LiMn[sub.2]O[sub.4], a significant cathode material for lithium-ion batteries, has garnered considerable attention due to its low cost and environmental friendliness. However, its widespread application is constrained by its rapid capacity degradation and short cycle life at elevated temperatures. To enhance the electrochemical performance of LiMn[sub.2]O[sub.4], we employed a liquid-phase co-precipitation and calcination method to incorporate Cr[sup.3+] into the LiMn[sub.2]O[sub.4] cathode material, successfully synthesizing a series of LiCr[sub.x]Mn[sub.2−x]O[sub.4] (x = 0~0.06). The prepared Cr-doped samples exhibited an excellent spinel structure and a unique truncated octahedral morphology. Additionally, the substitution of Mn[sup.3+] in LiMn[sub.2]O[sub.4] by Cr[sup.3+], coupled with the significantly higher Cr-O bond energy compared to Mn-O bond energy, enhanced the stability of the crystal structure and inhibited the Jahn–Teller effect. Experimental results demonstrated that the optimized LiCr[sub.0.04]Mn[sub.1.96]O[sub.4] displayed superior electrochemical performance, with a capacity retention rate of 93.24% after 500 cycles under a 0.5C current density; even at 50 °C, the capacity retention rate remained at 86.46% after 350 cycles under a 0.5C current density. The polyhedral morphology formed by Cr doping in LiMn[sub.2]O[sub.4] offers an effective approach to achieving high-performance LiMn[sub.2]O[sub.4] cathode materials.