Development of New Conducting Salts

Regarding the anion, other types of anions free of halogen have been investigated. As can be seen from the above discussion, the frequently used anions such as BF4 contain halogen. Several research groups pointed out that toxic hydrogen fluoride (HF) might be formed due to the possible hydrolysis of these fluoro-complex 

Tetramethylammonium difluoro(oxalato)borate Tetramethylammonium bis(oxalato)borate 

FIGURE 2.47 Structure of TMADFOB, TMABOB, and TEABOB, which was studied in Reference 481. 

Apart from the organic cations, some attention has been focused on the inorganic cations such as LiX NaX MgX and CsX As mentioned previously, due to the small ionic size of LP, lithium salt-based organic electrolytes have been extensively used in hybrid ESs such as LICs [486]. Considerable studies have also reported the 

TEABF4 (61.6% capacitance retention vs. 75.5% capacitance retention after 10,000 cycles), which was related to the morphology change of the electrode materials after long cycling tests. 

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