4C快充锂离子电池的石墨负极和电解液设计

doi:10.19799/j.cnki.2095-4239.2025.0841

摘要/Abstract

摘要：

锂离子电池快速充电是电动汽车实现大规模经济成功的关键，4C快充技术亟待普及。针对石墨嵌锂动力学迟滞这一快充瓶颈，对石墨进行软碳包覆和电解液采用的乙酸乙酯（EA）溶剂是有效的解决方案。本文对石墨的软碳包覆方式（固相、液相）、包覆量（1.0%、1.5%）和电解液中的EA含量（10%、70%），开展3因子2水平全因子实验，系统验证了锂离子电池的内阻、存储性能和循环性能的响应情况。主要表现为通过包覆增加石墨无序度、通过添加EA增加电解液电导率可以改善内阻、但是劣化存储性能和循环性能。70% EA的内阻改善效果最佳，液相包覆内阻改善优于1.5%包覆量，直流内阻下降分别为21.12%、4.83%和2.53%。相应地，70% EA的存储性能劣化程度最高，液相包覆劣化程度次之，容量保持率下降分别为1.26%、1.17%，而1.5%包覆量对7天存储性能劣化，对28天存储性能无劣化。70% EA的4C快充循环性能劣化程度最高，液相包覆劣化程度与1.5%包覆量相当，600周容量保持率下降1.58%、0.35%、0.33%。70% EA的高温循环性能劣化程度最高，1.5%包覆量次之，600周容量保持率下降分别为0.97%、0.24%，但液相包覆对高温循环性能无劣化，表明液相包覆的优越性。本文为4C快充锂离子电池材料和体系设计提供了思路。

关键词: 锂离子电池, 石墨, 软碳包覆, 电解液, 乙酸乙酯

Abstract:

Fast-charging capability of lithium-ion batteries (LIBs) is crucial for the large-scale economic success of electric vehicles, making the widespread adoption of 4C fast-charging technology imperative. To address the sluggish kinetics of the lithium-ion intercalation into graphite, which is the key bottleneck for fast charging, applying soft carbon coating to graphite and utilizing ethyl acetate (EA) as the electrolyte solvent are effective solutions. This study conducted a 3-factor, 2-level full factorial experiment investigating the soft carbon coating methods (solid-phase, liquid-phase), the coating amount (1.0%, 1.5%) for graphite, and the EA content in electrolyte (10%, 70%), to systematically verify the response of internal resistance, storage performance, and cycling performance in LIBs. Increasing graphite disorder through coating and adding EA to enhance electrolyte conductivity optimize internal resistance while deteriorate storage and cycling performance. For internal resistance optimization, 70% EA demonstrated the most significant effect, liquid-phase coating outperformed 1.5% coating amount, achieving direct current internal resistance reductions of 21.12%, 4.83%, and 2.53%. For storage performance deterioration, 70% EA caused the largest extent and slightly more severe than liquid-phase coating, corresponding drops in capacity retention of 1.26% and 1.17%, 1.5% coating amount deteriorated 7-day storage performance but exhibited no observable deterioration in 28-day storage. For 4C fast-charging cycling performance deterioration, 70% EA induced the most critical severity, liquid-phase coating and 1.5% coating demonstrating comparable degradation, causing a decrease in the 600-cycle capacity retention of 1.58%, 0.35%, and 0.33%. For high-temperature cycling performance deterioration, 70% EA was the severest, followed by 1.5% coating, leading to a decrease in the 600-cycle capacity retention of 0.97% and 0.24%, liquid-phase coating caused no observable deterioration, indicating its superiority. This work provides valuable insights for material and system design in 4C fast-charging LIBs.

Key words: Lithium-ion battery, Graphite, Soft carbon coating, Electrolyte, Ethyl acetate

李圆圆, 刘欣, 刘超辉, 陈宇, 杨小龙, 钱振扬, 杨卓群, 郭万颖. 4C快充锂离子电池的石墨负极和电解液设计[J]. 储能科学与技术, doi: 10.19799/j.cnki.2095-4239.2025.0841.

Yuanyuan LI, Xin LIU, Chaohui LIU, Yu CHEN, Xiaolong YANG, Zhenyang QIAN, Zhuoqun YANG, Wanying GUO. Graphite anode and electrolyte design for 4C fast-charging lithium-ion batteries[J]. Energy Storage Science and Technology, doi: 10.19799/j.cnki.2095-4239.2025.0841.

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参考文献 20

[1]	ADAM A, WANDT J, KNOBBE E, et al. Fast-charging of automotive lithium-ion cells: In-situ lithium-plating detection and comparison of different cell designs[J]. Journal of the Electrochemical Society, 2020, 167(13):130503.
[2]	WEISS M, RUESS R, KASNATSCHEEW J, et al. Fast charging of lithium-ion batteries: A review of materials aspects[J]. Advanced Energy Materials, 2021, 11(33):2101126.
[3]	杲齐新, 赵景腾, 李国兴. 锂离子电池快速充电研究进展[J]. 储能科学与技术, 2023, 12(7):2166-2184.
	GAO Qixin, ZHAO Jingteng, LI Guoxing. Research progress of fast-charging lithium-ion batteries[J]. Energy Storage Science and Technology, 2023, 12(7):2166-2184.
[4]	ZHONG C, WENG S, WANG Z, et al. Kinetic limits and enhancement of graphite anode for fast-charging lithium-ion batteries[J]. Nano Energy, 2023, 117:108894.
[5]	SHU W, ZENG Z, QIN M, et al. Perspective on fast-charging lithium-ion batteries: Mechanism, detection, and suppression of graphite anode lithium plating[J]. Energy Storage Materials, 2025, 81:104479.
[6]	WENG S, YANG G, ZHANG S, et al. Kinetic limits of graphite anode for fast-charging lithium-ion batteries[J]. Nano-Micro Letters, 2023, 15(1):215.
[7]	廖雅贇, 周峰, 张颖曦, 等. 锂离子电池快充石墨负极材料研究进展[J]. 储能科学与技术, 2024, 13(1):130-142.
	LIAO Yayun, ZHOU Feng, ZHANG Yingxi, et al. Research progress of fast-charging graphite anode materials for lithium-ion batteries [J]. Energy Storage Science and Technology, 2024, 13(1):130-142.
[8]	DONG Y, LIU C, RUI M, et al. Review on graphite anodes for fast-charging lithium-ion batteries: Mechanism, modification and characterizations[J]. Advanced Functional Materials, 2025, n/a(n/a):2506190.
[9]	LEI S, ZENG Z, CHENG S, et al. Fast-charging of lithium-ion batteries: A review of electrolyte design aspects[J]. Battery Energy, 2023, 2(5):20230018.
[10]	LI J, GUO C, TAO L, et al. Electrode and electrolyte design strategies toward fast-charging lithium-ion batteries[J]. Advanced Functional Materials, 2024, 34(49):2409097.
[11]	HE J, MENG J, HUANG Y. Challenges and recent progress in fast-charging lithium-ion battery materials[J]. Journal of Power Sources, 2023, 570:232965.
[12]	ZHANG D, LI L, ZHANG W, et al. Research progress on electrolytes for fast-charging lithium-ion batteries[J]. Chinese Chemical Letters, 2023, 34(1):107122.
[13]	QIN Q, LI X, WANG Z, et al. Experimental and simulation study of direct current resistance decomposition in large size cylindrical lithium-ion battery[J]. Electrochimica Acta, 2023, 465:142947.
[14]	LIN W, ZHU M, FAN Y, et al. Low temperature lithium-ion batteries electrolytes: Rational design, advancements, and future perspectives[J]. Journal of Alloys and Compounds, 2022, 905:164163.
[15]	LU Y, ZHAO C-Z, HUANG J-Q, et al. The timescale identification decoupling complicated kinetic processes in lithium batteries[J]. Joule, 2022, 6(6):1172-1198.
[16]	NIU P, YANG K, SONG Z, et al. An efficient electrochemical optimizer for the distribution of relaxation times of lithium-ion batteries[J]. Journal of Power Sources, 2024, 605:234489.
[17]	ZHU H, RUSSELL J A, FANG Z, et al. A comparison of solid electrolyte interphase formation and evolution on highly oriented pyrolytic and disordered graphite negative electrodes in lithium-ion batteries[J]. Small, 2021, 17(52):2105292.
[18]	LIU X, YIN L, REN D, et al. In situ observation of thermal-driven degradation and safety concerns of lithiated graphite anode[J]. Nature Communications, 2021, 12(1):4235.
[19]	LU B, CHENG D, SREENARAYANAN B, et al. Key parameters in determining the reactivity of lithium metal battery[J]. ACS Energy Letters, 2023, 8(7):3230-3238.
[20]	LI Z, YAO N, YU L, et al. Inhibiting gas generation to achieve ultralong-lifespan lithium-ion batteries at low temperatures[J]. Matter, 2023, 6(7):2274-2292.