Lithium Sulfur Batteries Presented by Timothy Cleary Oral English Assessment Exam

A brief two part presentation: 1. Review of LFP batteries 2 A brief two part presentation: 1. Review of LFP batteries 2. Introduction to Li-S batteries

Review of Lithium Iron Phosphate Batteries

Electrospun Nanofiber-Based Anodes, Cathodes, and Separators for Advanced Lithium-Ion Batteries

Electrospun Nanofiber-Based Anodes, Cathodes, and Separators for Advanced Lithium-Ion Batteries

Electrospun Nanofiber-Based Anodes, Cathodes, and Separators for Advanced Lithium-Ion Batteries

LFP – Charge / Discharge Voltage Curve https://www.researchgate.net/publication/257225829_Battery_state_of_the_charge_estimation_using_Kalman_filtering?_sg=CN-p_-hH2iRBrtLRY36Crlzb7WQauvvhaWzxTmvczySwahTLowX5j63GxTgzo_CzP-6gA9uH2xeRjZnYv4LC6yxXpIwhesdVZA

Introduction to Lithium Sulfur Batteries

Interesting Voltage Curve Tight voltage range (2.5 to 1.4 V) Different charge/discharge profiles Discharge - S8 to Li2S (2.3V) High plateau reduction of long chain lithium polysulfides (Li2Sx, 4 <= x) (2.1V) Low plateau reduction of short chain lithium polysulfides (Li2Sx, x <= 4) Charge - Li2S to S8 (Copyright 2013, Royal Society of Chemistry)

High Energy Density (G. Zhou) This Ragone plot shows how Li-S battery performance compares to other popular electrical energy storage systems. On par with the energy density of a fuel cells and the power density of Li-Ion batteries 5x specific energy of Li-Ion (theoretical) 2500 (Li-S) vs 500 (Li-ion) [Wh/kg] (G. Zhou)

Sulfur Inexpensive Non toxic 10th most abundant element

Safety Performance Impressive nail puncture performance, no smoke and almost no energy release

What cause this cell to fail? Shuttle effect / Sulfur insulation The soluble polysulfide intermediates (Li2Sx, 3 ≤ x ≤ 8) in the organic liquid electrolyte during the cycle process bring about the polysulfide “shuttle effect,” which leads to irreversible capacity loss and corrosion on the lithium–metal anode [Yang, Wang]. Insulating characteristic of sulfur and its discharge products (Li2S), leading to a low utilization of active material [Wang]; Structural instability Large volumetric expansion/shrinkage (80%) during discharge/charge due to the different densities of sulfur (2.03 g cm−3) and lithium sulfides (1.67 g cm−3), resulting in an instability of the electrode structure; As a result, todays realistic life of a LiS cell is about 500 to 1000 cycles

Research Goals In preparation for when Li-S cells become commercially available Modeling & characterization Application of observers/estimators for SOC prediction Life cycle optimization

Companies Making Li-S Cells OXIS Energy – Achieving ~ 500 cycle and bosting 400 Wh/kg SAFT – Li SO2 (primary battery) Sony – Announces plans for commercialization of lithium- sulfur (Li-S) / magnesium sulfur (Mg-S) by 2020

References 2017_Book_DesignFabricationAndElectroche © Springer Nature Singapore Pte Ltd. 2017 G. Zhou, Design, Fabrication and Electrochemical Performance of Nanostructured Carbon Based Materials for High-Energy Lithium–Sulfur Batteries, Springer Theses, DOI 10.1007/978-981-10-3406-0_1 OXIS Energy - https://oxisenergy.com/technology/ Wang D-W et al (2013) Carbon-sulfur composites for Li–S batteries: status and prospects. J Mater Chem A 1(33):9382–9394 Wang D-W et al (2012) A microporous-mesoporous carbon with graphitic structure for a high-rate stable sulfur cathode in carbonate solvent-based Li–S batteries. Phys Chem Chem Phys 14(24):8703–8710 Yang Y, Zheng G, Cui Y (2013) Nanostructured sulfur cathodes. Chem Soc Rev 42(7):3018–3032