Synthesis and electrochemical characterization of Hard Carbon(HC) anode and HC/P2-Na2/3Ni1/3Mn2/3O2 full cell characteristics for Na-ion battery

Abstract

Chapter 1 focuses on the need for cleaner and sustainable energy storage technologies. In the realm of energy, the global community faces two pivotal challenges: transitioning from fossil fuel-dependent energy sources to renewable alternatives for electricity generation, and shifting ground transportation from internal combustion engine-driven vehicles to electric propulsion systems. While considerable strides have been made in harnessing renewable energies from diverse sources such as wind and solar radiation, the development of cost-effective energy storage devices, such as batteries, to meet the rising energy demands lags significantly behind. With the rapid evolution of portable electronics and electric mobility, energy storage technologies have assumed a central position in research endeavors, playing a pivotal role in the effective utilization of green and clean energy resources. Among these technologies, Lithium ion Batteries (LIBs) have spearheaded a revolution in energy storage across portable electronics, grid storage, and Electric Vehicles (EVs), owing to their flexible, lightweight design, rechargeability, and high energy density. The fast kinetics of Li+ ions, facilitating rapid transfer of ions during charge-discharge cycles, renders LIBs a dependable and energy-efficient choice. Chapter 2 meticulously elucidates the intricacies of hard carbon, encompassing its structure, properties, and synthesis methods, emphasizing its significance in advancing battery technologies. Carbonaceous materials have historically played a pivotal role as negative electrode materials for alkali-ion batteries, owing to their abundance, low cost, and tunable structural properties. Within this discourse, various analytical techniques like (X-Ray diffraction, high resolution transmission electron microscopy, BET) used to evaluate the structural and morphological properties of hard carbon have been discussed in detail. Chapter 3 deals with the synthesis of a carbon-based anode material through the pyrolysis of tissue waste over temperatures ranging from 800 to 1400°C. Waste pyrolyzed at 1400°C exhibited the highest de-sodiation capacity of 350 mAhg⁻¹ at a rate of 20 mAg⁻¹, accompanied by commendable cyclic stability evidenced by a 70% capacity retention after 400 cycles at 100 mAg⁻¹. The investigation further delved into scrutinizing the morphology, structure, and surface chemistry of the cycled hard carbon electrodes using ex-situ Field Emission Scanning Electron Microscopy (FE-SEM), High-Resolution Transmission Electron Microscopy (HRTEM), Energy Dispersive X-ray Spectroscopy (EDX), and X-ray Photoelectron Spectroscopy (XPS). In i addition, the assessment of diffusion kinetics parameters was carried out via Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV) measurements. In the Chapter 4, the focus is on synthesizing an anode material derived from Pistachio shells, an abundantly available waste material, through a pyrolysis process conducted within a temperature range of 900 to 1400°C. Remarkably, the material treated at the upper limit of this temperature range, specifically at 1400°C, demonstrates exceptional electrochemical performance, showing a reversible discharge capacity of 302 mAhg-1 and a plateau capacity of 223 mAhg-1 at 10 mAg-1. Notably, this material exhibits stable cyclic performance, retaining an impressive 80% of its capacity after 500 cycles at 200 mAg-1. To gain insights into the morphological, structural, and surface chemical characteristics of the cycled hard carbon anode materials, comprehensive analyses were conducted utilizing ex-situ field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. Furthermore, the study delves into the sodiation and desodiation mechanisms of the synthesized hard carbon employing operando Raman spectroscopy. Additionally, diffusion kinetic parameters were elucidated through Electrochemical Impedance Spectroscopy (EIS) and cyclic voltammetry (CV) methods. In Chapter 5, we focus on the synthesis of carbonaceous anode material for sodium-ion batteries (SIBs) through the pyrolysis of sugarcane bagasse, a readily available biowaste. Sugarcane bagasse comprises carbon-rich compounds such as hemicellulose, lignin, and cellulose, which impede the graphitization process during pyrolysis. Consequently, the resulting material exhibits a highly disordered and porous structure, characterized by flake-like formations and increased interplanar spacing. These structural features are instrumental in facilitating faster sodium ion transport and enhancing sodium storage capabilities. The electrochemical performance of the synthesized hard carbon, particularly the sample pyrolyzed at 900°C (referred to as SW 900), demonstrates remarkable characteristics. Specifically, SW 900 exhibits a second-cycle discharge capacity of 300 mAhg-1 at 25 mAg-1, indicative of its high energy storage capacity. Even after undergoing 300 cycles at a higher current density of 100 mAg-1, SW 900 retains over 65% of its initial capacity, showcasing its robust cycling stability. In Chapter 6, we have developed a 3D porous carbon-based anode material by subjecting pea skin waste, in conjunction with an in-situ MgO/NaCl template, to pyrolysis at 750℃ (referred to as PSC-MN). The inclusion of MgO and NaCl serves a dual purpose, acting as mesopore and macropore templates, thereby facilitating the creation of a porous structure while concurrently reducing the impedance associated with the transfer of Na+ ions from the electrolyte to the ii micropores. Notably, the presence of MgO contributes to enhanced porosity and structural integrity. Furthermore, to explore the influence of MgO, we synthesized 3D porous carbon without MgO (referred to as PSC-N) and conducted an in-depth analysis of the structural and electrochemical properties of both PSC-MN and PSC-N. The precise control over porosity induced by the optimal presence of the NaCl template, coupled with a reduced BET surface area and the presence of mesopores, has culminated in the exceptional electrochemical performance of these materials. Specifically, PSC-MN exhibits a reversible charge capacity of 240 mAhg-1 at 20 mAg-1, with a notable 60% capacity retention after 250 cycles at 100mAg-1. To gain insights into the electrochemical kinetics of the PSC-MN and PSC-N samples, we employed Electrochemical Impedance Spectroscopy (EIS) and cyclic voltammetry (CV) methods. Additionally, ex-situ scanning electron microscopy (SEM) and Raman spectroscopy were utilized to further elucidate the sodium storage mechanism during the charge-discharge process. Overall, our findings underscore the significance of tailored porosity control and template utilization in optimizing the electrochemical properties of carbon-based anode materials for SIBs. Chapter 7 highlights the conclusion of thesis. This underscores the effect of the carbonization temperature of all the four hard carbon precursors (with different morphologies) on the structural properties, surface chemistry and the electrochemical properties. Plateau capacity an important aspect of the electrochemical performance is compared for all the biowaste precursors and the role of morphology in determining the plateau capacity has also been highlighted in this section. Chapter 8 reveals the future scope of work like making hard carbon / metal oxide composites and evaluating their structural and electrochemical performance in half and full configuration for Na-ion battery.