Electrochemical properties of boric ester electrolytes with high potential cathodefor lithium ion batteries
50130238 Kazutaka Hotta

Introduction
Lithium-ion batteries are currently produced on aExperimental

large scale mainly as equipment for powering portable

Boric ester synthesized boric acid (B(OH)3) andelectronic devices, but simultaneously intensive

alcohols. Composition of liquid electrolytes wereresearch is carried out on the development of large andshown in Table 1. Li/LNM cell was prepared, then thehigh power batteries for powering hybrid electric

cell charge-discharge measurement was performed.

vehicles (HEVs) and plug-in HEVs.
We have reported that boric ester electrolytes showed

Result and discussion

the high oxidation potential.

Charge-discharge behaviors of Li/LNM cell inBoric esters exhibit

preferable physical and electrochemical properties thatare tunable due to substituents R (Fig. 1).

Theelectrolyte A indicate the large irreversible current
probably resulting from oxidative decompose ofboron atom possesses a vacant p-obital and thus Lewis

EC/EMC. However, the cell was operated in electlolyte

acid. They are able to bind the counter anions ofB and C up to 20 cycles. This is considered to be forlithium salts and solvent molecules. Boric esters could

high anodic stability of boric ester electrolyte.

be synthesized from inexpensive starting materials
such as boric acid (B(OH)3) and alcohols. A boric ester

Conclusion

is found to have a high oxidative stability, therefore theThe Li/LNM cell with high potential cathode wasuse of LiNi0.5Mn1.5O4 (LNM) can be expected. In thisoperated in boric ester electrolyte.

study, we measured charge-discharge of Li/LNM cellin boric ester electrolyte.

Reference1) Y. Yalyosef, at el, J. Power Sources. 106 (2005)

ORRO

B

OR

BCN : R = electron
withdrawing grop
BIP : R = alkyl
BTFE : R = fluoroalkyl

Fig. 1 Chemical structures of boric esters.
Table 1 Compositions of electrolytes.
Electrolyte

Salts [mol kg-1]

Solvents

A

LiBF4 = 1.0

EC/EMC = 1/1 (vol)B

LiBF4 = 0.7

BIP/BCN = 1/2 (mol)C

LiBF4 = 1.0

BTFE/BCN = 1/2 (mol) + EC/EMC= 1/1 (vol) = 1/1 (vol)Synthesis and evaluation of a molecule which has the molecule oxygen
capture ability
Shota TEZUKA
Department of Materials Science & Chemical Engineering, Shizuoka University, Naka-ku,Hamamatsu, Shizuoka 432-8561, Japan
Blood is an electrolyte in which salts and proteins are dissolved. One of thefunctions of blood is to bind the molecular oxygen at the lung and to bring them to distal cells
to maintain an animal life. Heme proteins such as myoglobin (1) play a central role forabsorption and desorption of the molecular oxygen. Eventually the molecular oxygen
immediately dissolves in blood than in normal saline. Attention has been long paid topioneer the artificial blood system so as to create a blood substitute for instance.

あMyoglobin (1)Picket fence porphyrin (2)(5.60, 22.3)(6.60, 25.0)(6.50, 24.8)

Perfluorocarbons (3): the numbers in parentheses denote the solubility ofmolecular oxygen and carbon dioxide as molar ratio (solute mol x 103/solvent mol).
Synthetic hemes, such as iron (II) picket fence porphyrin (2),1 took part in thisexploration giving rise to a clue to the rudimentary knowledge of the blood function, but thesesynthetic molecules were unsuitable for quantity production. Perfluorocarbons (3) also
absorb the molecular oxygen but the practical application of these remains mostlyunexploited.2,3,4

side view

top view

Scheme 1 Schematic representation of reversible molecular oxygen
absorption-desorption with a synthetic aromatic
Recently we have found that a newly designed electron-sufficient aromatic is capableof interacting with the molecular oxygen in solution. The fluorescence from the aromatic
decreases as the oxygen gas was introduced into the solution probably because of the resulting
proximity of the oxygen to the aromatic: the photo-excited energy at the aromatic seems to beinactivated by the O-O vibration in the molecular oxygen bound. The fluorescence intensity
partially recovers upon introducing an inert gas (N2, Ar) into the solution indicating that theinteraction observed is reversible (Scheme 1). A simple phenol derivative also decrements
its fluorescence when the oxygen gas was introduced but the bathochromic shift occurs
simultaneously. Furthermore the decrescence and shift are irreversible. These exhibit thatthe aromatic enables the reversible oxygen absorption while a simple phenol derivative
merely undergoes irreversible oxidation.

1. “Picket fence porphyrins. Synthetic models for oxygen binding hemoproteins,” Collman, J.
P.; Gagne, R. R.; Reed, C.; Halbert, T. R.; Lang, G.; Robinson, W. T. J. Am. Chem. Soc.,
1975, 97 (6), 1427–1439.
2. "Survival of Mammals Breathing Organic Liquids Equilibrated with Oxygen at
Atmospheric Pressure," Clark, L. C., Jr.; Gollan, F. Science 1975, 152, 1755–1756.
3. "The Effects of Structure on the Viscosities of Perfluoroalkyl Ethers and Amines," Brice, T.
J.; Coon, R. I. J. Am. Chem. Soc. 1953, 75, 2921–2925.
4. "Physical Properties and Gas Solubilities in Selected Fluorinated Ethers," Tham, M. K. et al.
J. Chem. Eng. Data 1973, 18, 385–386.

Charge-discharge behaviors of carbonate ester electrolytes
containing alkoxyboroxine
50912098 Naoki Numada

Introduction
We have recently shown that a specific alkoxyboroxine of tri-isopropoxy boroxine(TiPBx) highly stabilized interfacial reactions between both the cathode/anode and carbonate
ester electrolyte probably resulting from formation of a stable solid state electrolyte interface(SEI).1) Here we report on the further efficiency of alkoxyboroxines at low concentration (ca.
0.01 mol kg-1) and on charge-discharge behaviors of the lithium ion battery with the electrolyte
containing alkoxyboroxines.

Experimental
Alkoxyboroxines were synthesized from boric acid anhydride (B2O3) and corresponding
boric esters (B(OR)3). The electrolytes were prepared from alkoxyboroxines dissolving into 1.0mol kg-1 LiBF4 in EC (ethylene carbonate)/EMC (ethyl methyl carbonate) (1/1 vol). The
charge-discharge behaviors were conducted with the LiMn2O4 cathode and Li metal anode. The
anodic stability of electrolytes was evaluated by Cyclic voltammetry (CV) with LiMn2O4 thinfilm cathode.
ROB(OR) 3 + B2O3

BOO

B

ORO

B
OR

R =-CH(CH3)2:TiPBx
R = -CH 2CH2CH3 :TnPBx:TMBx
R = -CH 3Scheme.1 synthsis of Alkoxyboroxines

Result and discussion

Acknowledgement

We acknowledge NEDO ofJapan for finance support.

References
1) T. Horino et al., J.Electrochem.Soc.,
157 (2010) 677.

Discharge capacity [mAh/g]

Chemical structures of alkoxyboroxines were drawn in the inset of Fig.1 and thedischarge capacity as the index of charge-discharge behavior was shown in Fig.1. The capacity
decreased for the electrolyte without TiPBx while it was improved on addition of a small
amount of TiPBx (0.01 mol kg-1). In contrast to TiPBx, TnPBx showed low effect. TMBx
indicated rather negative effect ascompared with additive free. CV measurements exhibited thatthe interface of electrolytes/LiMn2O4 thin film was highly stabilized at the high voltage even atthelow
TiPBx
concentration
120
presumably because of formation ofstable SEI. In fact the secondary ion100
microprobe mass spectrometry indicatedexistence of B atom at the LiMn2O4 thinOOR80 ROB
B
film surface.
R = -CH(CH 3) 2: TiPBx
OO
B= -CH 2 CH 2CH3 : TnPBx
OR: TMBx= -CH 3
● TiPBx free-1▲ TiPBx 0.01 mol kg

604020001020304050Cycle number

Fig.1 Discharge capacity vs cycle number.
electrolyte: 1.0 mol kg-1 LiBF4 in EC/EMC (1/1vol) with/without TiPBx, cathode: LiMn2O4,anode: Li, cut-off voltage: 3.5-4.7 V, rate: 0.5 C,
temperature: 300C.

Synthesis of magnesium salt for multivalent ion secondary battery
Kosuke MIZUNO
Department of Materials Science & Chemical Engineering, Shizuoka University, Naka-ku,Hamamatsu, Shizuoka 432-8561, JapanThe urgent and general requirements for secondary batteries are to be small and light:
thus a battery possessing high energy density per unit volume (V·A·hour/dcm3) and mass(V·A·hour/kg) is highly demanded. Alkali metals such as lithium and sodium lose one
electron upon oxidation while multivalent metals such as magnesium, zinc, or aluminum give
multi electrons. Therefore a multivalent ion battery may increase its energy density. The
oxidation reactions, redox potentials, and densities of the metals are summarized in Scheme 1.

Scheme 1 Oxidation reactions, redox potentials, and densities of lithium,magnesium, zinc, and aluminum.
The magnesium recently attracts attentions among the multivalent metals due to low
reactivity and abundance. Thus magnesium metal could be adopted as the anode material
bringing about the extremely high capacity battery. However battery materials especially forthe cathode and electrolyte are still underdeveloped and bound candidates are not yet brought
forward so far. A magnesium supporting salt as an electrolyte component is also well
unexplored yet. A salt pairing with two monovalent anion such as chloride (Cl-) involves thetwo-step dissociation which always indicates low dissociation constant in total (equation 1).
A salt pairing with one divalent anion such as sulfonate (SO42-) also shows low dissociation
constant because of the localized two negative charges (equation 2). A divalent anion inwhich the charges are delocalized is required (equation 3).

Recently we have found that a divalent anion possessing cluster structure exhibits thetwo negative charges are delocalized on all over anion surface promising high dissociation
degree (Figure 1). Then we have synthesized the magnesium salt with the dianion by meansof the cation exchange procedure.
Figure 1 The most stable structure andelectron distribution (red) of the cluster
dianion by theoretical calculation（B3LYP/6-311+G(d,p)）

1. “Picket fence porphyrins. Synthetic models for oxygen binding hemoproteins,” Collman, J.
P.; Gagne, R. R.; Reed, C.; Halbert, T. R.; Lang, G.; Robinson, W. T. J. Am. Chem. Soc.,
1975, 97 (6), 1427–1439.
2. "Survival of Mammals Breathing Organic Liquids Equilibrated with Oxygen at
Atmospheric Pressure," Clark, L. C., Jr.; Gollan, F. Science 1975, 152, 1755–1756.
3. "The Effects of Structure on the Viscosities of Perfluoroalkyl Ethers and Amines," Brice, T.
J.; Coon, R. I. J. Am. Chem. Soc. 1953, 75, 2921–2925.
4. "Physical Properties and Gas Solubilities in Selected Fluorinated Ethers," Tham, M. K. et al.
J. Chem. Eng. Data 1973, 18, 385–386.

Novel liquid electrolyte with nitrile compound possessing highoxidation potential
50912100

Miho Hatazaki

Introduction
The urgent and general requirement for lithium ion batteries installed in vehicles is to besmall and light: thus a battery exhibiting high energy density per unit volume (V·A·hour/dcm3) andmass (V·A·hour/kg) is highly demanded. Attention has been therefore paid to development of anovel liquid electrolyte possessing high oxidation potential. Nitrile compounds such as adiponitrile
generally have high oxidation potential but lack the high dipole moment resulting in low dielectric
constant. Here we synthesize a nitrile compound with high oxidation potential as well as high dipolemoment.
Experimental
1 was synthesized from malononitrile and 1,5-dibromopentan according to Scheme1.
Liquid electrolytes were prepared by dissolving of LiPF6 in a mixed solvent of ethylene
carbonate/ethyl methyl carbonate /1 (1/1/1 weight, 1.0 mol/kg). I measured ionic conductivity of thiselectrolyte. Oxidation potential of the electrolytes was evaluated by linear sweep voltammetry (LSV).
Intermolecular interaction of carbonate and 1 molecules was estimated by 1H- and 13C-NMR
spectroscopy.
Results and discussions
Ab initio calculation with B3LYP/6DBU , Br(CH2) 5Br
311+G** indicates that 1 has the high dipole
moment of 5.246 debye while adiponitrile has 0.0 NCCH2CN
NC CN80OC , 2hdebye. The ionic conductivity has improved when1
1 was added into EC/EMC (Fig. 1). This was
Scheme 1 Synthesis of 1
derived from the valid dielectric constant of
the electrolyte
resulting from high dipole moment in 1. LSV indicated that the carbonete ester electrolyte showed
the oxidation potential at 4.5 V while the electrolyte with 1 showed at 5.3 V (Fig. 2). NMR
spectroscopy suggested the intermolecular interaction between carbonate and 1 molecules. The
electron deficient molecule of 1 carrying electron withdrawing nitriles reduced the electron density
on the carbonete molecules through the interaction eventually giving high oxidation potential.
80℃

50℃

30℃

0℃
2Current dencity[mA/cm ]0.5

1.0 mol/kg LiPF6 in EC/EMC
1.0 mol/kg LiPF6 in EC/EMC/1

1.0 mol/kg LiPF6 in EC/EMC
1.0 mol/kg LiPF6 in EC/EMC/1

0.4
0.3
0.2
0.1
0
3.5

4.5

5.5

6.5

Voltage[V]Fig.1 Ionic conductivity for electrolytes.
applied voltage: 10 mV,
range of frequency:106~0.1 Hz

Fig.2 LSV (V vs Li/Li+) for electrolytes.
scan rate: 0.1 mV/sec, working electrode: C,
reference electrode: Li.