物理化学学报 >> 2025, Vol. 41 >> Issue (4): 100037.doi: 10.3866/PKU.WHXB202408007

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通过简单的浆料添加剂调整电极-电解液界面以实现稳定的高电压锂离子电池

黄奥羽1, 许君1, 黄玉1, 储圭1, 王卯1, 王黎丽2,*(), 孙永奇3, 蒋臻4, 朱晓波1,*()   

  1. 1 长沙理工大学材料科学与工程, 长沙 410114
    2 合肥大学先进电池关键材料与技术重点实验室, 安徽省锂离子动力与储能电池产业共性技术研究中心, 合肥 230601
    3 中南大学冶金与环境学院, 科技部清洁冶金国际联合研究中心, 长沙 410114
    4 School of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong, Wollongong, NSW, 2522 Australia
  • 收稿日期:2024-08-07 修回日期:2024-08-30 录用日期:2024-08-30 发布日期:2024-12-28
  • 通讯作者: Email: wangll@hfuu.edu.cn (王黎丽)xbzhu@csust.edu.cn (朱晓波)
  • 基金资助:
    国家自然科学基金(52202210); 湖南省自然科学基金(2024JJ5024); 安徽省高校优秀青年人才支持计划(重点)项目(2024JJ5024)

Tailoring Electrode-Electrolyte Interfaces via a Simple Slurry Additive for Stable High-Voltage Lithium-Ion Batteries

Aoyu Huang1, Jun Xu1, Yu Huang1, Gui Chu1, Mao Wang1, Lili Wang2,*(), Yongqi Sun3, Zhen Jiang4, Xiaobo Zhu1,*()   

  1. 1 College of Materials Science and Engineering, Changsha University of Science and Technology, Changsha 410114, China
    2 Key Laboratory of Materials and Technologies for Advanced Batteries, LIB Technology Center of Anhui Province, Hefei University, Hefei 230601, China
    3 School of Metallurgy and Environment and National Center for International Cooperation of Clean Metallurgy, Central South University, Changsha 410083, China
    4 School of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong, Wollongong, NSW, 2522 Australia
  • Received:2024-08-07 Revised:2024-08-30 Accepted:2024-08-30 Published:2024-12-28
  • Contact: Email: wangll@hfuu.edu.cn (Lili Wang)xbzhu@csust.edu.cn (Xiaobo Zhu)
  • Supported by:
    the National Natural Science Foundation of China(52202210); Natural Science Foundation of Hunan Province(2024JJ5024); the Key Projects for the Excellent Talent Foundation of Education Department of Anhui Province(2024JJ5024)

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摘要：

5 Ⅴ级LiNi0.5Mn1.5O4 (LNMO)作为无钴正极材料，满足了对廉价高性能锂离子电池(LIBs)日益增长的需求。然而，由于高工作电位，LNMO在与商用电解液的界面上存在不稳定性问题。本文提出使用硅酸四乙酯作为LNMO正极浆料添加剂。这种简单的方法能够在电极制备过程中在正极表面原位形成乙氧基官能化的聚硅氧烷薄膜。它不仅有助于形成稳固的人工正极-电解液界面，还能清除氢氟酸(HF)以抑制有害的化学串扰影响。因此，与原始正极相比，优化后的LNMO正极在半电池中表现出显著提高的循环稳定性(1000次循环后容量保持率为84.6% vs. 51.4%)，在与商用石墨负极配对的全电池中也是如此(500次循环后保持率为83.3% vs. 53.4%)，并在50 ℃的高温测试环境下和软包电池中进一步得到验证，这一简单策略有望为开发下一代高性能锂离子电池铺平道路。

关键词: LiNi0.5Mn1.5O4, 高电压, 正极-电解质界面, 浆料添加剂, 过渡金属溶解, 锂离子电池

Abstract:

5 Ⅴ-class LiNi0.5Mn1.5O4 (LNMO) cathode material is emerging as a promising cobalt-free alternative to meet the growing demand for affordable, high-performance lithium-ion batteries (LIBs). However, LNMO faces significant electrochemical challenges, particularly interfacial instability with commercial electrolytes due to its high operating potentials. This instability leads to the dissolution of transition metals and consequently electrode crosstalk, which severely deteriorates electrochemical performance. Surface coating is extensively investigated to reduce interfacial side reactions for enhanced cycling stability. Traditional methods typically require multiple steps, including dispersion, mixing, drying, and calcination, which can be time-consuming and complex. Additionally, the resulting ceramic coatings are often rigid and unevenly distributed due to lattice mismatches, potentially leading to poor interfacial contact and increased resistance. In this study, tetraethyl orthosilicate (TEOS) is proposed as a streamlined slurry additive to in situ form an ethoxy-functional polysiloxane (EPS) film on the surface of LNMO particles during electrode preparation. Post-mortem X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma (ICP) analyses reveal the crucial role of the EPS film in addressing interfacial instability issues. First, the EPS film serves as an artificial cathode-electrolyte interface (CEI) with a robust Si―O―Si bonding network, which is less vulnerable under high potentials. Second, the remaining ethoxy-functional groups in EPS scavenge HF by forming stable Si―F bonds, thereby suppressing the detrimental transition metal dissolution and crosstalk. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) further confirm the stability of the EPS film and the enhanced structural stability of the modified LNMO. Galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) results demonstrate that EPS reduces the overall impedance and improves ion diffusion kinetics by forming stable electrode-electrolyte interfaces. As a result, compared to the baseline, the optimized LNMO cathode exhibits significantly improved cycling stability in both half cells (84.6% vs. 51.4% capacity retention after 1000 cycles) and full cells when paired with commercial graphite anodes (83.3% vs. 53.4% retention after 500 cycles). This strategy, further validated under elevated temperatures of 50 ℃ and in pouch-type cells, is expected to pave the way for the development of next-generation high-performance LIBs.

Key words: LiNi0.5Mn1.5O4, High voltage, Cathode-electrolyte interface, Slurry additive, Transition metal dissolution, Lithium-ion battery