揭示了4.6V的高压液态COO2的谷物边界破裂诱导的容量衰减
Haocong Yi1, Yuhao Du1, Jianjun Fang1
1School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen 518055, P. R. China.
ACS applied materials & interfaces
|August 28, 2023
概括
高压电池电极滚动可能会导致高压氧化 (HV-LCO) 中的谷物边界裂纹. 这种裂改变了接口结构,导致容量衰减和批量损坏,突出了需要更强大的修改的需要.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 电池技术 电池技术
背景情况:
- 氧化 (LCO) 是电池中一个关键的阴极材料.
- 高压LCO (HV-LCO) 提供了更好的能量密度,但面临着稳定性挑战.
- 电极滚动是一种标准的制造工艺,用于提高电池性能.
研究的目的:
- 为了研究电极滚动对表面修改HV-LCO的稳定性的影响.
- 了解制HV-LCO电极容量衰减背后的机制.
- 提出一个新的接口结构概念来解释循环稳定性恶化.
主要方法:
- 合成的HV-LCO具有表面Al/F丰富和螺旋增强结构.
- 在HV-LCO电极下进行高压滚动.
- 使用循环测试和结构特征 (隐含) 分析了电极结构变化和电化学性能.
主要成果:
- 在HV-LCO中,电极滚动会诱导谷物边界裂纹 (GBC).
- 形成GBC改变了接口结构从旋转到旋转和非保护性边界相的混合体.
- 这种结构变化加快了产能衰减,并造成了批量损坏,包括内部裂和不活跃阶段.
结论:
- 仅仅表面修改不足以实现稳定的HV-LCO阴极.
- 由于GBC的形成和接口的改变,电极滚动引入了重要的稳定性风险.
- 更深入地了解接口结构对于开发先进的LCO阴极材料至关重要.
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