Organoboron polymer electrolytes

II. Anion-Trapping-Type Organoboron Polymer Electrolytes via... 

IV Facile Preparation of Organoboron Polymer Electrolytes via Dehydrocoupling Reaction of 9-Borabicyclo[3.3.1]nonane... 

Organoboron Polymer Electrolytes for Selective Lithium Cation Transport... 

IV. FACILE PREPARATION OF ORGANOBORON POLYMER ELECTROLYTES VIA DEHYDROCOUPLING REACTION OF 9-BORABICYCLO[3.3.1JNONANE AND... 

Ion-conductive properties of anion-trapping-type organoboron polymer electrolytes was evaluated after adding lithium salts (Fig. 3). In these systems, ionic conductivity of 3.05 X 10 s 5.22 X 10 6Scm 1 was observed at 50°C. This indicates... 

A nion- Trapping- Type Organoboron Polymer Electrolytes 179... 

The lithium transference number (l,) of these organoboron polymer electrolytes was evaluated by combination of dc polarization and ac impedance methods, as reported by Evans et al44 (Table 1). The observed t+ at 30°C was 0.50-0.35, indicating that anions were significantly trapped in these systems. Owing to the stronger Lewis acidity of the alkylborane unit, alkylborane-type polymers showed relatively higher t+. 

Table 1 Lithium Transference Number t+ for Organoboron Polymer Electrolytes...

The lithium transference number (t+) of a polymer bearing PEO550 side chain/LiCF3S03 was found to be 0.38 at 30°C. This value implies that anions were effectively trapped by organoboron units, similar to linear organoboron polymer electrolytes. 

A 9-borabicyclo[3.1.1]nonane (9-BBN)45 is one of the most well-known hydroborane reagents. Because of the commercial availability of 9-BBN, facile preparation of organoboron polymer electrolytes using this reagent should be an industrially beneficial approach.34,36... 

Reactions of organoboron polymer electrolytes with aryllithium reagents suffered low conversion due to relatively low reactivity of the mesitylborane unit. Moreover, incorporation of aryl substituent in side chains resulted in higher glass-polymer electrolyte-transition temperatures. 

A variety of organoboron polymer electrolytes were successfully prepared by hydroboration polymerization or dehydrocoupling polymerization. Investigations of the ion conductive properties of these polymers are summarized in Table 7. From this systematic study using defined organoboron polymers, it was clearly demonstrated that incorporation of organoboron anion receptors or lithium borate structures are fruitful approaches to improve the lithium transference number of an ion conductive matrix. 

Design of organoboron polymer electrolytes will continue to have a great deal of potential based on the ability to tailor boron atoms. This is an attractive approach for single ion conductive materials. 

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