Screening and Analysis of Carbon additives used to improve DCA of Lead Acid Batteries Presenter: Robert Hansen, Undergraduate, Department of Materials Science and Engineering Co-Researcher: Shengyi Li, Graduate Student, Department of Materials Science and Engineering Faculty Adviser, Dr. Benjamin Church, Department of Materials Science and Engineering

Introduction Lead Acid battery technology use is limited to SLI. DCA of lead Acid Batteries is naturally poor. Addition of Carbon additives can improve DCA properties Carbon additives act as a catalyst to gas evolution. Figure 1: PbSO4 Dis/Charge vs particle size

Methodology - Cyclic Voltammetry(CV) Two electrode system Micro Powder Electrode (working electrode) Carbon additive is packed into the tip 50 µm2 electrode surface area. Reference electrode Mercury/Mercurous Sulfate (Hg/Hg2SO4, saturated K2SO4) design Records current with respect to voltage Electrodes hooked up to potentiostat and computer Potential (voltage) Window: -1.8V to 1.9 Volts Scan rate of: 20µV/s 5 cycles Solution H2SO4(aq) 1.28g/mL + Na2SO4(aq) 15g/L + PbO saturated. Figure 2: Setup of CV test in Faraday cage.

Cyclic Voltammetry graph Cathodic region: Hydrogen evolution –greater the slope, more H2. Peak - Reduction of O2 gas. Anodic region: Oxygen evolution – greater the slope, more O2. Peak - Oxidation of H2 gas. Missing information: No peaks representing active materials Peaks around point of hydrogen evolution Anodic Region Cathodic region Figure 5: CV Cycle 5 for all plain carbon samples.

H2 evolution potential (V) O2 evolution potential (V) Graphical Analysis Sample Cycle No. H2 Slope H2 evolution potential (V) O2 Slope O2 evolution potential (V) Stability Window PBX 31 1 -1.03E-06 -1.603 -2.26E-06 1.695 3.298 5 -9.19E-07 -1.468 -5.97E-07 1.796 3.264 BP45A111 -2.35E-05 -1.128 -2.27E-05 1.607 2.735 -2.55E-05 -1.246 -2.09E-05 1.497 2.743 PBX 51 -7.01E-05 -1.404 -7.76E-05 1.679 3.083 -7.29E-05 -1.255 -7.25E-05 1.562 2.817 PBX 51 MODA -5.47E-05 -1.213 -3.90E-05 1.886 3.099 -7.51E-05 -1.323 -7.07E-05 1.587 2.91 PBX 51 MODB -4.60E-05 -1.024 - 1.9 2.924 -3.58E-05 -1.476 -3.36E-05 1.77 3.246 PBX 51 MODB No PbO -6.51E-05 -1.279 -5.58E-05 1.657 2.936 -6.57E-05 -1.28 -6.10E-05 1.557 2.837 PBX135 -2.04E-05 -1.093 -1.09E-05 1.868 2.961 -1.37E-05 -1.141 -2.03E-05 1.808 2.949

Conclusions Conclusions: PBX 31 preformed the best in CV testing, primary candidate. BP45A111 and PBX 135 performance was acceptable. Will be used in future stages of DCA project. Methodology worked well for measuring the catalytic effects of carbon additives on electrolysis in a lead acid cell. No oxidation or reduction peaks of active materials were present in CV results.

Re-evaluation of the electrode design! Future Work Re-evaluation of the electrode design! Design - Electrode slurry spread onto lead foil Feature a large surface area compared to micro electrode Prototype negative plate for down the road.

Acknowledgments Thankyou to Johnson Controls Inc. for providing materials and Lab space to conduct research. Additional funding provided by the Office of Undergraduate Research through the SURF Grant.

Thankyou for your time.

Bibliography Hu, Jingcheng, Chengbin Wu, Xinle Wang, and Yonglang Guo. "Additives of Suppressing Hydrogen Evolution at Carbon-Containing Negative Plates of Valve-Regulated Lead-Acid Batteries." Int. J. Electrochem. Sci (2016): n. pag. Web. 4 Apr. 2016. Pavlov, Detchko. (2011). Lead-Acid Batteries - Science and Technology - A Handbook of Lead- Acid Battery Technology and its Influence on the Product. Elsevier.