Towards high energy density sodium ion batteries through electrolyte optimization
Towards high energy density sodium ion batteries through electrolyte optimization
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DOI：
10.1039/c3ee41379a
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发表时间：
2013-08-01
影响因子：
32.5
通讯作者：
Palacin, M. Rosa
中科院分区：
文献类型：
--
作者：
Ponrouch, Alexandre;Dedryvere, Remi;Palacin, M. Rosa
对钠离子电解质配方进行了优化，并对其与正负极材料的相容性进行了研究。发现EC:PC:DMC和EC:PC:DME具有最佳的离子电导率和较低的粘度。然而，在这种电解质中测试的硬碳负极材料表现出显著的性能差异，其原因是SEI的电阻率不同，导致二甲醚作为共溶剂使用时极化过大，在低电位下容量损失。发现EC0.45:PC0.45:DMC0.1是硬碳电极在持续循环时具有良好倍率能力和高容量的最佳组合。该材料与正极性Na3V2(PO4)(2)F-3 （NVPF）电极的相容性也得到了证实，其组装的全钠离子电池显示出3.65 V的工作电压，极低的极化和良好的容量保持，在循环超过120次后，NVPF循环约为97 mA h g(-1)，具有令人满意的库仑效率（>98.5%）和非常好的功率性能。这样的数值导致的能量密度可与当前最先进的锂离子技术相媲美。
A comprehensive study is reported entailing optimization of sodium ion electrolyte formulation and compatibility studies with positive and negative electrode materials. EC:PC:DMC and EC:PC:DME were found to exhibit optimum ionic conductivities and lower viscosities. Yet, hard carbon negative electrode materials tested in such electrolytes exhibit significant differences in performance, rooted in the different resistivity of the SEI, which results in too large polarization and concomitant loss of capacity at low potentials when DME is used as a co-solvent. EC0.45:PC0.45:DMC0.1 was found to be the optimum composition resulting in good rate capability and high capacity upon sustained cycling for hard carbon electrodes. Its compatibility with positive Na3V2(PO4)(2)F-3 (NVPF) electrodes was also confirmed, which led to the assembly of full Na-ion cells displaying an operation voltage of 3.65 V, very low polarisation and excellent capacity retention upon cycling with ca. 97 mA h g(-1) of NVPF after more than 120 cycles together with satisfactory coulombic efficiency (>98.5%) and very good power performance. Such values lead to energy densities comparable to those of the current state-of-the-art lithium-ion technology.