期刊
ELECTROCHIMICA ACTA
卷 222, 期 -, 页码 1086-1093出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.electacta.2016.11.079
关键词
Organic anode; Potassium terephthalate; Lattice stability; Cyclic and rate capability; Li-ion batteries
资金
- UESTC [ZYGX2015KYQD058]
- National Science Foundation of China [11234013, 21473022, 21673033, 51603028]
- Science and Technology Bureau of Sichuan Province of China [2015HH0033]
- Opening Project of State Key Laboratory of Polymer Materials Engineering (Sichuan University) [Sklpme2016-4-23]
- University Grants Committee of the HKSAR Area of Excellence Scheme [AoE/P-03/08]
Terephthalate (C8H4O42-) moiety with stable oxidized and reduced states is widely employed as the organic anode in batteries. However, along with the dissolution problem, the representative lithium terephthalate (Li2TP) exhibited unsatisfactory cyclic and rate capability. Herein, based on the calculated and experimental results, we demonstrated that potassium terephthalate (K2TP) possesses superior cyclic and rate capability in Li-ion batteries. On one hand, due to the larger radius of K+ ion, K2TP exhibits more stable lattice architecture than Li2TP for the better size matching between cations and anions; On the other hand, K+ ion in K2TP could remain electrochemical inertness even its standard redox potential (-2.931 V) is higher than Li+ ion (-3.040 V). Meanwhile, the K-O bond in K2TP is calculated to be more ionic while the Li-O bond in Li2TP has more covalent character. The ionic K-O bond of K2TP could further enhance its dissolution resistance against non-polar electrolyte. Indeed, after its electronic conductivity and particle dispersity were improved by mixing with graphene, the modified K2TP anode could exhibit very stable capacity of similar to 122 mAh g(-1) at 8C for 500 cycles, which is comparable or even superior to the state-of-the-art Li-ion batteries currently reported for small organic molecules. (C) 2016 Elsevier Ltd. All rights reserved.
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