石墨电极力学性能和界面剥离强度的实验研究
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摘要
石墨电极已被广泛应用于商业锂离子电池,因而对于石墨电极的力学性能要求也在不断提高。通过表征和研究石墨电极的力学性能和界面剥离强度,能够为石墨电极相关技术的可靠性研究提供必要的数据支持和理论指导,从而使石墨电极得到合理和可靠的使用。本文运用拉伸和180°剥离实验,分别研究了石墨电极原样、电解液浸泡后的电极以及不同充电状态(SOC)下电极的力学性能和界面剥离强度。拉伸实验结果表明,充满电状态下电极材料的断裂形式是脆性断裂,而原样电极、电解液浸泡后电极以及完全放电状态下电极均表现出韧性断裂。180°剥离实验结果表明,电极的活性层与集流体之间界面剥离强度在充满电状态下的值比完全放电后的值大。经过电解液浸泡后的电极活性层与集流体之间界面剥离强度则与原样电极的值相同。经过1000次充放电循环后,石墨电极活性层与集流体之间界面剥离强度则远远低于未经过充放电循环电极的值。
Graphite electrode has been widely applied in commercial lithium-ion battery,and the requirement of graphite electrode mechanical properties is also continually increasing.Understanding and characterizing basic mechanical properties and interfacial peeling strength of graphite electrode will provide necessary data support and theoretical guidance for the reliability of graphite electrode related technology,so that graphite electrode can be used reasonably and reliably.In this paper,mechanical properties and interfacial peeling strength of graphite electrode,including graphite electrode original sample,electrode after immersion of electrolyte and electrode with different charged states were investigated,respectively based on tensile experiment and 180° peeling experiment. Tensile experimental results show that the fracture mode of electrode material with full charged state is brittle fracture,while the fracture modes of original electrode,electrode after immersion of electrolyte and electrode with fully discharged state are all ductile fracture.In addition,180 degrees peeling experimental results show that the interfacial peeling strength between active layer and current collector with fully discharged state is higher than the value of electrode with fully charged state.The electrode original sample and electrode after immersion of electrolyte have the similar peeling force between active layer and current collector.After 1000 charge-discharge cycles,the interfacial peeling strength between active layer and current collector is much lower than the value of graphite electrode without charge-discharge cycles.
Graphite electrode has been widely applied in commercial lithium-ion battery,and the requirement of graphite electrode mechanical properties is also continually increasing.Understanding and characterizing basic mechanical properties and interfacial peeling strength of graphite electrode will provide necessary data support and theoretical guidance for the reliability of graphite electrode related technology,so that graphite electrode can be used reasonably and reliably.In this paper,mechanical properties and interfacial peeling strength of graphite electrode,including graphite electrode original sample,electrode after immersion of electrolyte and electrode with different charged states were investigated,respectively based on tensile experiment and 180° peeling experiment. Tensile experimental results show that the fracture mode of electrode material with full charged state is brittle fracture,while the fracture modes of original electrode,electrode after immersion of electrolyte and electrode with fully discharged state are all ductile fracture.In addition,180 degrees peeling experimental results show that the interfacial peeling strength between active layer and current collector with fully discharged state is higher than the value of electrode with fully charged state.The electrode original sample and electrode after immersion of electrolyte have the similar peeling force between active layer and current collector.After 1000 charge-discharge cycles,the interfacial peeling strength between active layer and current collector is much lower than the value of graphite electrode without charge-discharge cycles.
引文
[1] Daniel C,Besenhard J O.Hand book of battery materials(2nd edition)[M].Weinheim:Wiley-VCH Verlag&Co.KGaA,2011.
[2]朱建宇,冯捷敏,郭战胜,等.锂离子电池用铜箔集流体的力学性能分析[J].储能科学与技术,2014,3(4):360-363(ZHU Jianyu,FENG Jiemin,GUO Zhansheng,et al.Mechanical properties of copper current collection foils of Li-ion batteries[J].Energy Storage Science and Technology,2014,3(4):360-363(in Chinese))
[3]郭战胜,王宇晖,朱建宇,等.铝箔力学性能的实验研究[J].实验力学,2016,31(4):451-457(GUO Zhansheng,WANG Yuhui,ZHU Jianyu,et al.Experimental Research of mechanical properties for aluminum foil[J].Journal of Experimental Mechanics,2016,31(4):451-457(in Chinese))
[4] Cao Y,Xiao L,Ai X,et al.Surface-modified graphite as an improved intercalating anode for lithium-ion batteries[J].Electrochemical and Solid-State Letters,2003,6(2):A30-A33.
[5] Choi J W,Aurbach D.Promise and reality of post-lithium-ion batteries with high energy densities[J].Nature Reviews Materials,2016,1(4):16013.
[6] Obrovac M N,Christensen L,Le D B,et al.Alloy design for lithium-ion battery anodes[J].Journal of the Electrochemical Society,2007,154(9):A849-A855.
[7] Yoo M,Frank C W,Mori S,et al.Effect of poly(vinylidene fluoride)binder crystallinity and graphite structure on the mechanical strength of the composite anode in a lithium ion battery[J].Polymer,2003,44(15):4197-4204.
[8] Lee J H,Paik U,Hackley V A,et al.Effect of poly(acrylic acid)on adhesion strength and electrochemical performance of natural graphite negative electrode for lithium-ion batteries[J].Journal of Power Sources,2006,161(1):612-616.
[9] Jeon H,Cho I,Jo H,et al.Highly rough copper current collector:improving adhesion property between a silicon electrode and current collector for flexible lithium-ion batteries[J].Rsc Advances,2017,7(57):35681-35686.
[10] GB/T 228.1-2010,金属箔材拉伸试验方法[S].北京:中国标准出版社,2010(GB/T 228.1-2010,Standard test methods of tension testing of metallic foil[S].Beijing:China Standard Press,2010(in Chinese))
[11] ASTM D3330-2010,Standard test method for peel adhesion of pressure-sensitive tape[S].American Society of Testing and Materials Press,2010.
[12] Pinson M B,Bazant M Z.Theory of SEI formation in rechargeable batteries:capacity fade,accelerated aging and lifetime prediction[J].Journal of the Electrochemical Society,2003,160(2):A243-A250.
[13] Lin D,Liu Y,Cui Y.Reviving the lithium metal anode for high-energy batteries[J].Nature Nanotechnology,2017,12(3):194-206.
[14] Harris S J,Rahani E K,Shenoy V B.Direct in situ observation and numerical simulations of non-shrinking-core behavior in an MCMB graphite composite[J].Journal of the Electrochemical Society,2012,159(9):A1501-A1507.
[15]任凤章,刘平,翟健,等.剥离法测量钛基体和不锈钢基体镍膜的界面结合能[J].材料热处理学报,2005,26(1):65-69(REN Fengzhang,LIU Ping,ZHAI Jian,et al.Interface bonding energy measurement in Ni films/Ti or stainless steel substrates systems by peeling test[J].Transactions of Materials&Heat Treatment,2005,26(1):65-69(in Chinese))
[2]朱建宇,冯捷敏,郭战胜,等.锂离子电池用铜箔集流体的力学性能分析[J].储能科学与技术,2014,3(4):360-363(ZHU Jianyu,FENG Jiemin,GUO Zhansheng,et al.Mechanical properties of copper current collection foils of Li-ion batteries[J].Energy Storage Science and Technology,2014,3(4):360-363(in Chinese))
[3]郭战胜,王宇晖,朱建宇,等.铝箔力学性能的实验研究[J].实验力学,2016,31(4):451-457(GUO Zhansheng,WANG Yuhui,ZHU Jianyu,et al.Experimental Research of mechanical properties for aluminum foil[J].Journal of Experimental Mechanics,2016,31(4):451-457(in Chinese))
[4] Cao Y,Xiao L,Ai X,et al.Surface-modified graphite as an improved intercalating anode for lithium-ion batteries[J].Electrochemical and Solid-State Letters,2003,6(2):A30-A33.
[5] Choi J W,Aurbach D.Promise and reality of post-lithium-ion batteries with high energy densities[J].Nature Reviews Materials,2016,1(4):16013.
[6] Obrovac M N,Christensen L,Le D B,et al.Alloy design for lithium-ion battery anodes[J].Journal of the Electrochemical Society,2007,154(9):A849-A855.
[7] Yoo M,Frank C W,Mori S,et al.Effect of poly(vinylidene fluoride)binder crystallinity and graphite structure on the mechanical strength of the composite anode in a lithium ion battery[J].Polymer,2003,44(15):4197-4204.
[8] Lee J H,Paik U,Hackley V A,et al.Effect of poly(acrylic acid)on adhesion strength and electrochemical performance of natural graphite negative electrode for lithium-ion batteries[J].Journal of Power Sources,2006,161(1):612-616.
[9] Jeon H,Cho I,Jo H,et al.Highly rough copper current collector:improving adhesion property between a silicon electrode and current collector for flexible lithium-ion batteries[J].Rsc Advances,2017,7(57):35681-35686.
[10] GB/T 228.1-2010,金属箔材拉伸试验方法[S].北京:中国标准出版社,2010(GB/T 228.1-2010,Standard test methods of tension testing of metallic foil[S].Beijing:China Standard Press,2010(in Chinese))
[11] ASTM D3330-2010,Standard test method for peel adhesion of pressure-sensitive tape[S].American Society of Testing and Materials Press,2010.
[12] Pinson M B,Bazant M Z.Theory of SEI formation in rechargeable batteries:capacity fade,accelerated aging and lifetime prediction[J].Journal of the Electrochemical Society,2003,160(2):A243-A250.
[13] Lin D,Liu Y,Cui Y.Reviving the lithium metal anode for high-energy batteries[J].Nature Nanotechnology,2017,12(3):194-206.
[14] Harris S J,Rahani E K,Shenoy V B.Direct in situ observation and numerical simulations of non-shrinking-core behavior in an MCMB graphite composite[J].Journal of the Electrochemical Society,2012,159(9):A1501-A1507.
[15]任凤章,刘平,翟健,等.剥离法测量钛基体和不锈钢基体镍膜的界面结合能[J].材料热处理学报,2005,26(1):65-69(REN Fengzhang,LIU Ping,ZHAI Jian,et al.Interface bonding energy measurement in Ni films/Ti or stainless steel substrates systems by peeling test[J].Transactions of Materials&Heat Treatment,2005,26(1):65-69(in Chinese))