Nano Structured RGO coated TiO 2 Negative Electrode Additive For Advanced Lead-Acid Battery

Transcription

1 Nano Structured RGO coated Negative Electrode Additive For Advanced Lead-Acid Battery Vangapally Naresh, Swati Jindal, S.A. Gaffor, Surendra K.Martha* Department of Chemistry Indian Institute of Technology Hyderabad Kandi, Sangereddy, , Telangana, INDIA * ; Tel:

2 Major Problems in Lead-Acid Battery Positive Plate Negative Plate Grid Corrosion Pb + 2 H 2 O PbO H + + 4e - Pb + PbO 2 2 PbO Sulfation Pb + H 2 SO 4 PbSO 4 + 2H + + 2e -

3 Major problems associated with Negative plate in a lead-acid battery Negative plates cannot accept the high charging current generated on regenerative braking. Batteries operate at PSoC which leads to rapid sulfation of the negative plate. 3

4 Decreasing Sulfation at the Negative Plate through Carbon Diluents Effect of Carbon Addition * Carbon in overall enhances the electrical conductivity of NAM It restricts formation of lead sulfate crystal growth; It acts as an capacitor by absorbing charge current, enabling battery to work under High rate Effect of Addition ** occupy the pores on the negative plate, hence work as an electrolyte absorber. Thus enhances PbSO 4 to Pb reduction during charge. References: * J. Xiang, P. Ding, H. Zhang, X. Wu, J. Chen, Y. Yang J. Power Sources 241 (2013) **P. Krivik, K. Micka, P. Baca, K.Tonar, P. Tosar J. Power Sources 209 (2012)

5 Synthesis of GO by modified Hummer s method 1 M graphite+ 1 M NaNO M H 2 SO 4 Stirring, 4hrs Add 6 M KMnO 4 slowly 1.Stirring,1hr 2.Δ,35 o C,1hr Add 1 M DIW 3 M DIW Stirring, 95 o C(reflux) Stirring,1hr Add 0.2 M of 30% H 2 O 2 Stirring,1hr Wash with 5%HCl & DIW Ref.: Hummers W. S, Hoffman R.E J. Am. Chem. Soc. 80 (1958) 1339 GO 5

6 Synthesis of RGO coated nanocomposite Graphene oxide + DIW+ C 2 H 5 OH+ 1.Sonication,1 hr 2.Sonication& Stirring,5hrs Suspension Solvothermal Synthesis suspension autoclave o C,3hrs 2.Filtration RGO coated

7 Physical and Structural Properties RGO d=0.36nm o d=0.35nm RGO o 101 E g (143.4cm -1 ) RGO D G Intensity(a.u.) Graphene Oxide 11 o 26 o d=0.82nm Graphite 002 2θ=26 o d=.33nm Intensity(a.u.) o RGO 101 d=0.35nm o d=0.35nm Intensity(a.u.) E g (143) B 1g (400) RGO D=1346cm -1 G=1576cm -1 E g (637) θ / degree θ / degree A 1g (513) Raman shift(cm -1 ) Crystallite size(nm) Graphite GO RGO RGO coated shows the masking effect on the Reduced Graphene Oxide.

8 Surface Morphology of Graphite, GO, RGO coated Graphite Graphene Oxide 100nm RGO coated 100nm 100nm RGO coated 100nm nm spherical particles 100nm

9 Structural and surface morphology of Leady oxide 1 1.α PbO 2.Pb Intensity / a.u nm θ / degree It consists mainly PbO and Pb Tetragonal structure Particle size ~ 200nm Particles were having the platelet like morphology

10 Technological scheme for electrode preparation Assembly of cells 2 positive- 1 negative 2.1 Ah

11 Comparative study of electrochemical performances of conventional and RGO- electrode additives during 1 st cycle Voltage / V Conventional RGO 1:10 RGO- 1:3 RGO at C/20 rate Time / hr Capacity: 1:3 RGO- > 1 : 10 RGO- > RGO > > Conventional Low IR drop: 1:3 RGO- > 1 : 10 RGO- > RGO > > Conventional

12 C-Rate and Cycling Stability Studies C rate Capacity / Ah C/20 C/10 C/5 Conventional RGO RGO- 1C Cycle Number Capacity / Ah Conventional RGO RGO Cycle number > 10 % improvement in capacity Cycling stability: RGO- > RGO > > Conventional

13 Cycling and impedance Studies Voltage / V C/5 rate Conventional 0.5wt% 0.25 wt% 1 wt% Cycle Number % increment in cycling stability -Z'' / Ohm conventional 1wt% 0.25 wt% 0.5 wt% Z' / Ohm At 100 th cycle Shows the less ohmic resistance

14 Cyclic voltammetry Studies Mechanism I / amp cm RGO- Conventional GRID NAM PbSO 4 H +, HSO4 - GRID NAM RGO- H +, HSO E / Volt PbSO 4 RGO- More current is required for the and RGO- additive cell compared to the conventional cell. Negative plate mechanism of the conventional cell, RGO coated additive cell

15 HRPSoC Capacity / Ah Convnetional RGO Cycle Number Cycle Number Conventional RGO Cycle set C/20 Rate Cycling HRPSoC cycle set

16 Current focus: Industrial prototype Laboratory prototype Industrial prototype

17 Conclusions Addition of RGO coated in to the negative active mass to reduce sulfation, consequently increase battery formation efficiency from 3 cycle to 1 cycle compare to the conventional cell % increase in discharge capacity(c-rate performances). 67 % increment in the first cycle compare to the conventional cell. Saving of 60 % formation power, 60 % man power compare to the conventional cell % more efficiency. Presence of RGO- shows the less ohmic resistance. 17

18 ACKNOWLEDGEMENTS Electrochemical Energy Storage Group at IIT- Hyderabad Supervisor: Dr. Surendra Kumar Martha NED Energy Limited, Hyderabad, India MHRD- for fellowship.

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