In order to explore the influence of the N/P ratio on the performance of lithium iron phosphate batteries, four kinds of N/P ratios of lithium-ion batteries were fabricated by using lithium iron phosphate as the cathode material and artificial graphite as the anode material. The effects of the first discharge efficiency; charge and discharge performance at different current intensities; charge and discharge DCR; discharge capacity at high and low temperatures; and cycle performance at 45 ℃ using different N/P ratios were studied by electrochemical technology. The results show that the charge DCRs of lithium-ion batteries at 1.10 and 1.14 are about 4 MΩ smaller than those of N/P ratios (1.02 and 1.06) at 60% and 30% SOC, making them less polarized under high current intensities and low temperature conditions. With the increase of N/P, the charging constant current ratio and capacity retention rate at 0 ℃ are improved. The capacity retention rate is still 91.8% after 1000 cycles at 45 ℃ when N/P is 1.10, which is significantly higher than other groups (N/P ratios at 1.02 and 1.06). This research could provide a theoretical basis for future investigation of the design and use of lithium iron phosphate batteries.
Keywords：lithium iron phosphate batteries
;
N/P ratio
;
charge and discharge at different current density
;
DCR
;
cycle performance
LIU Fanfeng. The influence of N/P ratio on the performance of lithium iron phosphate batteries[J]. Energy Storage Science and Technology, 2021, 10(4): 1325-1329
Fig. 2
Charge constant current ratio of batteries at different current intensity (a) and discharge capacity retention rate of batteries at different current intensity (b) under different N/P ratios (1.02, 1.06, 1.10 and 1.14)
杨续来, 张峥, 曹勇, 等. 高能量密度锂离子电池结构工程化技术探讨[J]. 储能科学与技术, 2020, 9(4): 1127-1136.YANG X L, ZHANG Z, CAO Y, et al. The structural engineering for achieving high energy density Li-ion batteries[J]. Energy Storage Science and Technology, 2020, 9(4): 1127-1136.
TARASCON J M, AMAND M. Issues and challenges facing rechargeable lithium batteries[M]//Materials for Sustainable Energy: A Collection of Peer-Reviewed Research and Review Articles from Nature Publishing Group. World Scientific, 2011: 171-179.
樊亚平, 晏莉琴, 简德超, 等. 锂离子电池失效中析锂现象的原位检测方法综述[J]. 储能科学与技术, 2019, 8(6): 1040-1049.FANG Y P, YAN L Q, JIAN D C, et al. Summary of in-situ detection methods for lithium evolution in lithium-ion battery failure[J]. Energy Storage Science and Technology, 2019, 8(6): 1040-1049.
杨涛, 刘文凤, 马梦月, 等. 三元锂离子动力电池衰减机理[J]. 应用化学, 2020, 37(10): 1181-1186.YANG T, LIU W F, MA M Y, et al. Attenuation mechanism of ternary lithium-ion power battery[J]. Applied Chemistry, 2020, 37(10): 1181-1186.
孙晓丽, 袁金秀, 张姗姗, 等. 蔬菜藤蔓衍生制备高性能锂离子电池硬碳负极材料[J]. 济南大学学报(自然科学版), 2021(3): 1-8.SUN X L, YUAN J X, ZHANG S S, et al. Preparation of high-performance hard carbon anode materials for lithium-ion batteries derived from vegetable vines[J]. Journal of Jinan University (Natural Science Edition), 2021(3): 1-8.
WU L Q, LI J C, DESHPANDE R D, et al. Aligned TiO2 notube arrays as durable lithium-ion battery negative electrodes[J]. The Journal of Physical Chemistry C, 2012, 116 (35): 18669-18677.
QIU B C, XING M Y, ZHANG J L. Mesoporous TiO2 nocrystals grown in situ on graphene aerogels for high photocatalysis and lithium-ion batteries[J]. Journal of the American Chemical Society, 2014, 136(16): 5852-5855.
POHLMANN S, RAMIREZ-CASTRO C, BALDUCCI A. The influence of conductive salt ion selection on EDLC electrolyte characteristics and carbon-electrolyte interaction[J]. Journal of the Electrochemical Society, 2015, 5: A5020-A5030.
WANG H J, ZHI L, LIU K Q, et al. Thin-sheet carbon nanomesh with an excellent electrocapacitive performance[J]. Advanced Functional Materials, 2015, 25: 5420-5427.
LI Z, LIU J, JIANG K R, et al. Carbonized nanocellulose sustainably boosts the performance of activated carbon in ionic liquid supercapacitors[J]. Nano Energy, 2016, 25: 161-169.
SUSANA V, JESUS P, MARC A, et al. Improving performance of electric double layer capacitors with a mixture of ionic liquid and acetonitrile as the electrolyte by using mass-balancing carbon electrodes[J]. Journal of the Electrochemical Society, 2013, 11: A2064-A2069.
MANAVALAN V, DUGGIRALA S R, TATA N R, et al. Electrode mass ratio impact on electrochemical capacitor performance[J]. Electrochimica Acta, 2019, 298: 347-359.
VITOR L M, ROBERTO M T, ANTHONY J R. Design considerations for ionic liquid based electrochemical double layer capacitors[J]. Electrochimica Acta, 2018, 270: 453-460.
LU H, HE L, LI X Y, et al. Ionic liquid-solvent mixture of propylene carbonate and 1,2-dimethoxyethane as electrolyte for electric doublelayer capacitor[J]. Journal of Materials Science: Materials in Electronics, 2019, 30: 13933-13938.
