electrochemical energy storage devices.pptx

regarding material selection characterization and fabrication

1. Electrochemical Energy Storage Devices Saikat Pal M.Sc. Applied Chemistry Ramakrishna Mission Vidyamandira, Belur Math – 711202, West Bengal

2. Internal Combustion Engine Electrochemical Energy Storage Devices 09-10-2024 2 Battery Fuel Cell Supercapacitor

3. Motivation 09-10-2024 3 The Future Influences the Present Game of E =QV + C sp .V 2   max

4. Battery Operation – Anatomy 09-10-2024 4 Lithium ion diffusion controlled pathway

5. Energy Storage Device: Battery Batteries are referred to as electrochemical cells: They store electrical energy in the form of chemical energy. Battery has two half cells: a cathode and another one is anode The reactions between those half cells occur concurrently and allow for the conversion of chemical energy to electrical energy by means of electron transfer through the external circuit. Perspective to the discharging phenomena Material with lower positive standard reduction potential is called the negative electrode or anode and while the material with higher positive standard reduction is called positive electrode or cathode. The electrolyte is an ion conducting material and separator is a membrane that physically prevents a direct contact between the two electrodes and allow ions but not electrons to pass through. 09-10-2024 5

6. Electrode Materials: Basic Requirement Cathode should have a high lithium chemical potential with respect to the anode in order to maximize the voltage. The cathode and anode materials should allow an insertion/extraction of a large amount of lithium to maximize the total charge which can be derived (more the number of lithium exchanged, more the number of electrons released or absorbed) If we are consider secondary/rechargeable lithium-ion batteries, then the lithium insertion/extraction should be reversible with no or minimal changes in the host structure over the entire range in order to provide a good cycle life. The materials should support a mixed conduction type behavior, with good electronic and lithium-ion conductivity. If either one is low, then the performance at higher current drawing rates will be impacted. The materials should be chemically stable without undergoing any reaction with the electrolyte The materials should be inexpensive, environmentally benign and lightweight. 09-10-2024 6

7. Ideal properties of a Li ion anode Material 09-10-2024 7 Till date graphite is the most widely used anode for Li. It can intercalate/deintercalate Li up to the composition LiC 6 , at which a stage Li atom (Li ion + electron) is present between every layer of the host graphite lattice and delivers a theoretical capacity of 372 mAhg −1 .It shows a potential of 0.15−0.25 V vs Li metal. However due to the low theoretical capacity and poor rate performance, graphite cannot meet the growing market demand of high energy and power density batteries. Consequently, anadromous research efforts have been devoted to develop new Li ion battery anodes with superior Li storage properties.

8. Anode for Sodium Ion Battery 09-10-2024 8 Theoretical capacity of Na metal is 1165 mA h g -1 . However, Na metal cannot be directly used as anode because of dendrite formation, high reactivity against electrolyte and low melting point of Na (97.7 o C) which also lead to safety problems. Therefore a number of other materials are investigated in order to find out appropriate anode F or SIBs . Should have low molecular weight and low density and be able to reversibly accommodate large amount of Na ions per unit formula in order to yield high volumetric (mAhcm -3 ) and gravimetric (mAhg -1 ) capacities It should possess a low potential to get high working voltage in full cell configuration It must not react or show any dissolution tendency in the solvent of the electrolyte

9. Case Study – I Amorphous MnO 2 ‑Modified FeOOH Ternary Composite with High Pseudocapacitance As Anode for Lithium-Ion Batteries 09-10-2024 9

10. Electrochemical Properties Analysis Role of FeOOH : Iron oxide, iron hydroxide and iron oxyhydroxide type materials show hybrid (Pseudocapacitance and redox) type electrochemical charge storage phenomenon. Drawbacks: less volume expansion during ion intercalation resulting only surface redox charge storage. Role of rGO: Conductive matrix for the electrode application. Role of MnO 2 : Contributes in volume expansion and amorphousness increases the capability beyond crystalline phase, formation of solid – electrolyte interface and enhances Li – ion intercalation 09-10-2024 10

11. Visualizations 09-10-2024 11 C yclic voltammograms (A, B, D, E, G, H) and corresponding galvanostatic profiles (C, F, I) representing various types of charge storage. The pseudocapacitive types presented here include (B) surface redox pseudocapacitance (hydrated RuO2 in acidic aqueous electrolytes), (D) intercalation pseudocapacitance (T-Nb2O5 in a Li+ nonaqueous electrolyte), and (E) combination of intercalation and surface redox pseudocapacitance (Ti 3 C 2 T x MXene in an acidic aqueous electrolyte). Cyclic voltammetry of (a) FeOOH and (c) FeOOH-rGO-MnO 2 batteries at 0.1 mVs –1 . First five galvanostatic charge (dotted)-discharge (straight) curves of (b) FeOOH and (d) FeOOH-rGO-MnO 2 batteries.

12. Current Density Profile: i (v) = av b Current density for ELD type Surface control or capacitive type semi infinite diffusion controlled kinetics follows I = C DL A v ( i ∝ v ) Current density for Charge Transfer In the same model when a charge transfer occur the Randles – Sevcik equation follows I = A ( i ∝ v 0.5 )   09-10-2024 12 Hybrid Model For either mixed control or hybrid sysem or finite-length diffusion (if the diffusion distance is smaller than ) i (V, v) follows the liner combination capacitive and diffusive i.e., A 1 (V)v + A 2 (V)v 0.5 By solving = A 1 (V)v 0.5 + A 2 (V) for different scan rate, we can distinguish the capacitive and diffusive contribution of a redox active electrode  

13. 09-10-2024 13 CV of FeOOH-rGO-MnO 2 anode at different scan rates, CV at 0.5 mVs –1 with the capacitive contribution separated from total current (red shaded region) Percentage contribution of capacitive and diffusion components at different scan rates, Capacitive contribution comparison of FeOOH -rGO and FeOOH-rGO-MnO 2 anodes.

14. Case Study – II NbO 2 a Highly Stable, Ultrafast Anode Material for Li- and Na-Ion Batteries 09-10-2024 14

15. Requirement of Alternate Anode The commercial graphite have issues like low specific capacity, limited fast charging opportunity and unstable solid – electrolyte interphase. The problems expedite the investigation of alternate opportunities Crystallographic structure engineered material, NbO 2 is found to be suitable for Li ion battery and Na ion battery 09-10-2024 15

16. Electronic Charge Storing Capability 09-10-2024 16 Li – Ion System Na – Ion System CV curves at various scan rate, capacitive contribution to total current at 0.2 mVs −1 scan rate variation of capacitive and diffusion contribution with respect to the scan rate CV curves at various scan rate, capacitive contribution to total current at 0.2 mVs −1 scan rate variation of capacitive and diffusion contribution with respect to the scan rate

17. End Note 09-10-2024 17 Thank you