The first rechargeable battery was invented in 1859 Research during the 70s and 80s developed the rechargeable battery we use worldwide Cost of production remains an important consideration for designing applicable techniques that can improve the Li-ion battery Illustration of Plante’s original lead-acid battery (1859). The first rechargeable battery ever made.

Electrochemical potential (between Al+/Al and Cu+/Cu) of the cell spontaneously accelerates electrons through the load, from the negatively charged anode to the positively charged cathode. E o Cell = E o Red,Cathode + E o Ox,Anode ΔG = -nFE o Cell ΔG 0: non-spontaneous

LiC 6  C 6 + Li + + e - During discharge the lithium ion passes through the electrolyte and the liberated electron travels across the load. The lithium ion and the free electron convene at the cathode after being released from the anode site. FePO 4 + Li + + e -  LiFePO 4 When charging the battery, the reverse process occurs. However, since electrons cannot spontaneously flow back to the anode, an applied potential difference (charger) provides the work.

Low rate capacities Low intrinsic electronic conductivity Low Li+ ion diffusion coefficient Atomic scale structure of the olivine crystal of LiFePO 4

Carbon Coating Improves the electronic conductivity on the surface of LiFePO 4 particles. Inhibits particle growth Prevents over oxidation of Fe 2+ to Fe 3+ during sintering by acting as a reducing agent.

Doping Element doping of heterogeneous ions to Li +, Fe 2+, or O 2- ion sites. Improves the lattice electronic conductivity of Lithium within the LiFePO 4 crystal. Does not improve the ionic conductivity of LiFePO 4.

Experiments reveal that gold nanostars exhibit great electronic conductivity. The morphology of spiky gold nanostars generates an increase in the local electric field. Enhance quantum tunneling probability between neighboring particles. Reduces the internal resistance of the batteries. Higher resistance to oxidation as compared to other composites that could be applied to cathode material. TEM image of Au nanostars sourced from the Physics Department of Howard University

Coin cell batteries are efficient for performing experiments because they require minimal use of materials for assembly. The hardware of the battery is extremely sensitive, especially the cathode and anode material. Precise mass measurements are essential for the calculation of charge and discharge capacities. Gold nanostars particles are applied to the cathode material before the assembly takes place.

Coin cells are assembled inside an environment with little to no water or oxygen molecules, which could precipitate unwarranted reactions. Active materials on the cathode and anode electrodes are strictly kept out of contact through every stage of the assembly process. Cleanliness is prioritized to prevent contamination of the cells and to maintain consistency in the batteries prepared.

Arbin BT2000 Battery Testing Station MITSPro is the software program that allows the user to create test schedules and collect data. Our experiments are concerned with the rate capacity of a battery and its degradation over many cycles. Charge and discharge capacity data is also collected and used with our mass measurements to compute specific charge/discharge capacities.

Improvement techniques to perfect the application of nanoparticles to cathode material are underway. Testing with nanoparticles has begun, with the X-series, but the current data is inconclusive. Improvements to the assembly process of our coincells are being experimented with to enhance performance yield and reproducibility. Further development of the X-series of coin cells will incorporate Au nanostars in solution with NMP.