EFFECT OF NOVEL ZnO ADDITIVE ON THE … · of lead-acid battery negative electrode ... carbon addtivives to negative active mass ... powerpoint presentation

LABAT’2017, 14 June 2017, Golden Sands Resort, BULGARIA

Bulgarian Academy of Sciences Institute of Electrochemistry and Energy Systems Lead-Acid Batteries Department

Bulgarian Academy of Sciences Institute of General and Inorganic Chemistry Laboratory of Crystal Chemistry of Composite Materials

EFFECT OF NOVEL ZnO ADDITIVE ON THE PERFORMANCE OF LEAD-ACID BATTERY NEGATIVE ELECTRODE

A. Aleksandrova, M. Matrakova, St. Ruevski, P. Nikolov, D. Pavlov – LABD, IEES-BAS

M. Markova–Velichkova, D. Kovacheva – LCCCM, IGIC-BAS

LABAT’2017, 14 June 2017, Golden Sands Resort, BULGARIA 2

INTRODUCTION CARBON ADDTIVIVES TO NEGATIVE ACTIVE MASS

Addition of different forms of carbon to negative active mass significantly improve HRPSoC performance of lead-acid batteries

Carbon additives can negatively impact the hydrogen evolution reaction as result increased water loss could be observed


INTRODUCTION SUPPRESSING HYDROGEN EVOLUTION REACTION

3

Addition of different materials to NAM formulation or to the electrolyte having high HER overvoltage Different metal oxides – Bi2O3, In2O3, La2O3, Sm2O3 and other Organic substances – derivatives of benzaldehyde, benzoic acid and other Metal ions – Bi, Zn and other

Recently, J. Xiang et al., (J. Power Sources 328 (2016) 8) proposed addition of ZnO to

NAM in order to improve HRPSoC performance and to reduce the Hydrogen evolution

reaction.


AIM OF PRESENT STUDY …

4

The goal of present study is to evaluate the effect of ZnO synthesized

by novel ultrasound-assisted precipitation method as additive to

negative active mass in order to improve HRPSoC cycling

performance of lead-acid battery and reduce the hydrogen evolution.


TESTED ADDITIVES

Powder of ZnO – synthesized by Sonochemical method (ultrasound-assisted

precipitation): starting compounds – 0.2M Zn(NO3)2.6H2O and 0.5M KOH, analytical grade

sonication time – 30 min

washed, filtered, dried at 80° C

20KHz, 750W ultrasonic processor Sonix, USA M. Markova-Velichkova et all., Bulg.Chem.Comm. 45 (2013) 427 – 433

(in text referred as ZnO Sono)

Powder of ZnO – commercially available product

(in text referred as ZnO Comm) 5


TESTED ADDITIVES PHASE COMPOSITION OF THE SAMPLES

Type of additive ZnO Comm ZnO Sono Specific surface area, m2 g-1 3 21

Mean crystal size, nm 175 22

Parameters, Å a = 3,2437(3) c = 5,2064(5)

a = 3,2512(2) c = 5,2120(3)

20 30 40 50 60 70 80

ZnO Comm

2Θ degrees

20111

220

0

103110

102

101

002

100

ZnO Sono

Inten

sity (

a.u.)

Hexagonal wurtzite ZnO structure with P63mc space group

M. Markova-Velichkova et all., Bulg.Chem.Comm. 45 (2013) 427 – 433

6


TESTED ADDITIVES PROPERTIES OF THE SAMPLES

200 300 400 500 600 7000

10

20

30

40 ZnO Comm ZnO Sono

Kub

elka -

Mun

k / un

its

Wavelength / nm3.1 3.2 3.3 3.4 3.5 3.6 3.70

5000

10000

15000

20000

Eg=3.43

ZnO Comm ZnO Sono

(hν F

(R ∞

))2

hν, eV

Eg=3.27

The n-type ZnO semiconductor: wide direct band gap higher electron mobility high breakdown voltages higher breakdown strength

Specifically in high powered

electronic devices

The value for sample ZnO Comm. (Eg= 3.27 eV) is lower rather than reported for the bulk zinc oxide , while the value of ultrasound-assisted obtained ZnO Sono (Eg= 3.43 eV) powder is almost equal to that of bulk ZnO (Eg= 3.37 eV)


Bulk ZnO-direct band gap of 3.37 eV

7


TESTED ADDITIVES MORPHOLOGY OF THE SAMPLES

ZnO Comm – irregular form and size particles

ZnO Sono – spindle-like particle shape homogeneous particle size distribution

ZnO Comm ZnO Sono


8


PERFORMANCE OF SMALL PASTED NEGATIVE PLATES DESIGN OF SMALL LEAD-ACID CELL

negative paste – 0.8 % BaSO4 of the weight of leady oxide (LO) - 0.2 % LignoSulfonate (LS) of the weight of LO - 0.5 % Hight surface area carbon black (HSC) of the weight of LO - 0.05 % ZnO Comm / 0.05 % ZnO Sono of the weight of LO

1 negative plate - Cn = 115 mAh 2 positive plates PE - separator electrolyte 1.28 sp. gr. H2SO4 (5 ml) reference electrode - Ag / Ag2SO4 / 1.28 H2SO reference cell scanning electron microscopy

9


NEGATIVE ACTIVE MASS CHARACTERISTICS MORPHOLOGY OF FORMED NEGATIVE PLATES

HSC Ref + ZnO Comm + ZnO Sono

the presence of ZnO in NAM has noticeable effect on Pb crystallization processes

10


NEGATIVE PLATES TESTING INITIAL C20 DISCHARGE CAPACITY

1 2 3100

110

120

130

140

150

160

Disc

harg

e cap

acity

/ mAh

/g

Cycle number

Ref HSC + ZnO Comm + ZnO Sono

Idch = I ch = C20-1.28

-1.30

-1.32

-1.34

-1.36

-1.38

-1.40

Neg

ative

plate

poten

tial /

V

+ ZnO CRef HSC + ZnO S

after third C20 cycle

the studied ZnO additives do not impact the C20 discharge performance of the test cells

11


HYDROGEN EVOLUTION REACTION NEGATIVE PLATES TESTING

after end of C20 test

sweep rate: 0.1 mV/sec

1 10 100-1.1

-1.2

-1.3

-1.4

-1.5

-1.6

Neg

ative

plate

poten

tial /

V Current / mA


addtion of 0.05% ZnO Sono to NAM

with 0.5% high surface area carbon

black increase hydrogen

overvoltage and thus suppress the

hydrogen evolution.

12


SIMPLIFIED HRPSoC CYCLING NEGATIVE PLATES TESTING

rest 10s

Id=C/1

char

ge

60s

Ich=2C

Time

50% SoCId=2C

60sdisc

harg

e

discharge with 1C A to 50% SoC

charge with 2C for 60 sec.

rest – 10 sec

discharge with 2C for 60 sec.

13


CYCLE LIFE TEST UNDER HRPSoC DUTY NEGATIVE PLATES TESTING

negative plates modified with 0.05% ZnO Sono

showed significant improvement in cycle life -

about 3600 cycles

the reference cell completed only 600 micro-

cycles 0 1000 2000 3000 4000-0.4

-0.6-0.8-1.0

-1.2-1.4-1.6-1.8

end - of - discharge potential


Pote

ntial

of ne

gativ

e plat

e / V

Cycle number

end - of - charge potential

14


NEGATIVE PLATES TESTING NEGATIVE PLATE POLARIZATION

during charge step

charge efficiency

V - Vocv = polarization

0 10 20 30 40 50 600

100200300

400500600

Polar

izatio

n / m

V

Time / sec

cycle # 1800

HSC + ZnO Comm + ZnO Sono

0 10 20 30 40 50 600

100200300

400500600

Polar

izatio

n / m

V

Time / sec

cycle # 300


HRPSoC cycle # 300 HRPSoC cycle # 1800

addition of 0.05 % ZnO Sono to NAM delay the H2 evolution during charge step

15


MORPHOLOGY OF NAM AFTER CYCLE LIFE TEST UNDER HRPSoC DUTY


NEGATIVE PLATES CHARACTERISTICS

16


SUMMARY

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ZnO powder material is successfully synthesized by novel ultrasound-assisted precipitation method.

The synthesized ZnO posses wider direct band gap than the commercial ZnO sample. The presence of ZnO in NAM has noticeable effect on Pb crystallization processes. Addition of 0.05% ZnO Sono to NAM with 0.5% high surface area carbon black results

to increase of the overvoltage of hydrogen evolution reaction. It has been demonstrate that negative plates containing 0.5% high surface area carbon

black and modified with 0.05% ZnO Sono showed significant improvement in HRPSoC cycling performance.


THANK YOU FOR YOUR ATTENTION


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EFFECT OF NOVEL ZnO ADDITIVE ON THE … · of lead-acid battery negative electrode ... carbon addtivives to negative active mass ... powerpoint presentation