Abnormal Excess Capacity of Conjugated Dicarboxylates in Lithium-Ion Batteries

作者：Lee Hyun Ho; Park Yuwon; Shin Kyoung Hee; Lee Kyu Tae^*; Hong Sung You

来源：ACS Applied Materials & Interfaces, 2014, 6(21): 19118-19126.

DOI：10.1021/am505090p

• lithium-ion batteries
• organic electrode materials
• anodes
• excess capacity

Lithium-ion batteries (LIBs) are considered to be key energy storage systems needed to secure reliable, sustainable, and clean energy sources. Redox-active organic compounds have been proposed as interesting candidates for electrode materials for the next-generation LIBs because of their flexible molecular design, recyclability, and low production cost. Despite wide interest, a molecular-level understanding of the electrochemical lithiations/delithiations of those materials remains rudimentary. We synthesized a set of pi-conjugated dicarboxylates and discovered unprecedented excess capacities for inverse-Wurster-type nonfused aromatic compounds (dilithium terephthalate and dilithium thiophene-2,5-dicarboxylate). Molecular structural investigations based on solid-state CP/MAS C-13 NMR combined with the stable isotope labeling method and ex situ X-ray diffraction were carried out to elucidate the origin of the excess reversible capacity. Interestingly, an open-chain-type dilithium muconate did not show an analogous behavior, signifying the key role played by the cyclic moiety in the electrochemical reaction.

• 出版日期2014-11-12