A Novel Sodium-Ion Composite Solid Electrolyte with Enhanced Electrochemical Performance through CeO2 Dispersoid

Abstract

The present invention pertains to a novel sodium-ion all-solid-state battery (ASSB) that significantly enhances electrochemical performance and safety by incorporating cerium oxide (CeO2) as dispersoid material within sodium solid-state electrolytes (SSEs). This innovation addresses the limitations of conventional sodium-ion batteries, particularly those utilizing organic liquid electrolytes, which pose risks such as flammability and leakage. By utilizing CeO2, the developed SSE exhibits improved ionic conductivity and electrochemical stability, achieving superior performance compared to existing technologies. The methodology involves the mechanical mixing of sodium nitrate and strontium nitrate with CeO2, followed by pellet formation and sintering. Comprehensive characterization techniques confirm the structural and thermal properties of the synthesized materials. Electrochemical testing demonstrates enhanced performance metrics, making this battery suitable for applications in renewable energy storage and electric vehicles. This invention represents a significant advancement in sustainable energy storage solutions.

Specification

Description:DESCRIPTION:
001. Field of Invention:
The present invention relates to rechargeable sodium-ion all solid-state batteries (ASSBs) with improved electrochemical performance and safety, utilizing CeO2 as dispersoid material in sodium solid-state electrolytes (SSEs).
002. Objectives:
1. Enhancement of Ionic Conductivity: To develop a sodium-ion all-solid-state battery (ASSB) that incorporates cerium oxide (CeO2) as a dispersoid to significantly improve the ionic conductivity of sodium solid-state electrolytes (SSEs), achieving a three-order-of-magnitude increase compared to traditional sodium nitrate-based materials.
2. Improved Electrochemical Performance: To provide a solid-state electrolyte system that demonstrates enhanced electrochemical performance, including stability and cycling durability, making it suitable for applications in renewable energy storage and electric vehicles.
3. Safety Improvement: To create a safer battery technology by eliminating the use of flammable liquid electrolytes, thereby reducing risks associated with leakage and fire hazards while maintaining high thermal stability across a wide temperature range.
4. Scalability and Cost-Effectiveness: To address scalability and cost concerns in the production of sodium-ion batteries by utilizing abundant and non-toxic materials, establishing a sustainable alternative to lithium-ion battery systems.
5. Comprehensive Characterization: To employ advanced characterization techniques such as X-ray Diffraction, also known as XRD, Scanning Electron Microscopy, also known as SEM, and Differential Scanning Calorimetry, also known as DSC to ensure the quality and performance of the synthesized solid-state electrolytes, leading to a better understanding of their structural and thermal properties.
003. Background of the Invention:
The invention of novel solid-state electrolytes for sodium-ion batteries (SIBs) arises from the need for safer, more efficient energy storage solutions. With concerns over lithium supply and environmental impact, sodium an abundant element emerges as a viable alternative.
Traditional SIBs utilize liquid electrolytes, which pose safety risks and often exhibit lower performance. Solid-state electrolytes provide greater security, energy density, and cycling stability. However, establishing high ionic conductivity and stable electrode interfaces continues to be a difficulty.
Recent advancements focus on innovative materials, such as sulphides and oxides, that exhibit superior ionic conductivity. Additionally, composite systems combining solid and oxide components are being explored to enhance performance. The ongoing study attempts to address scalability and cost-effectiveness, highlighting solid-state sodium-ion batteries as a possible approach for long-term energy storage.
004. Statement of the Problem
Rechargeable sodium-ion batteries (SIBs) have arisen as an acceptable substitute to lithium-ion batteries (LIBs) due to various challenges associated with LIBs, such as the scarcity of lithium resources, elevated costs, and safety concerns stemming from the use of liquid electrolytes. Sodium, being widely available and non-toxic, offers a more sustainable solution for energy storage. However, traditional sodium-ion battery systems, on the other hand, frequently use organic liquid electrolytes, which are flammable and have the potential leakage. Transitioning to solid-state electrolytes (SSEs) is essential to enhance safety while providing better thermal and electrochemical stability. Despite advancements, existing sodium solid-state electrolyte technologies still face significant hurdles in achieving the necessary ionic conductivity and overall performance required for practical applications. This invention seeks to address these critical issues by incorporating CeO2 as a dispersoid material within sodium solid-state electrolytes, aiming to improve the electrochemical efficiency and safety of sodium-ion all-solid-state batteries.
005. Summary of the Invention:
The invention provides a sodium-ion solid-state battery incorporating a novel solid-state electrolyte system that includes CeO2 dispersoid. The unique properties of these dispersoids improve the ionic conductivity and electrochemical performance of the SSE, addressing the critical challenges faced by existing sodium-ion technologies.
006. Detailed Description of the Invention:
1. Preparation of Dispersoid-Enhanced Solid-State Electrolytes:
o Materials Used:
 Nitrates of Sodium and strontium (NaNO3 and Sr(NO3)2) in a stoichiometric ratio of 85.32:14.68 were mixed to form the host compound.
 High-purity CeO2, with a particle size of less than 50 nm, was utilized as a dispersoid material.
o Methodology:
 The host powders were mechanically milled with CeO2 in an agate mortar with acetone for one hour to ensure a homogeneous mixture.
 Pellets were formed under a pressure of approximately 0.433 GPa and sintered at 200 °C for 24 hours.
2. Characterization of the Synthesized Pellets:
o X-ray Diffraction, also known as XRD: Utilized to analyses the structure of crystals and phase composition.
o Scanning Electron Microscopy, also known as SEM and Energy-Dispersive X-ray Spectroscopy, also known as EDAX: Employed to investigate the morphology and elemental composition of the materials.
o Fourier Transform Infrared Spectroscopy, also known as FTIR: Used to identify the groups of functional elements in the materials.
o Differential Scanning Calorimetry, also known as DSC: Employed to analyses the thermal characteristics of the synthesized pellets.
3. Electrochemical Testing:
o Impedance Spectroscopy: Conducted at frequency ranging from 1 Hz to 10 MHz and temperature ranging from of 303 K to 563 K, to evaluate the ionic conductivity and electrochemical performance.
4. Performance Evaluation:
o The ionic conductivity of the CeO2 dispersed solid electrolyte systems is assessed over a temperature range of 303 K to the melting point of the host material.
o An increase in conductivity of 3 orders of magnitude compared to the pure NaNO3 material is observed.
007. Brief Description of Drawings:
1. Figure 1 shows a flowchart for preparing nitrates of Sodium and Strontium (NaNO3 and Sr(NO3)2) mixed solid electrolyte single crystals and pellets using slow evaporation technique.
2. Figure 2 depicts a flowchart for synthesizing CeO2 dispersed solid electrolytes using homogenous mixture in the presence of acetone. , Claims:We Claim:
1. A sodium-ion all-solid-state battery (ASSB) comprising a solid-state electrolyte that includes sodium ion-conducting materials and dispersoid of CeO2, characterized by enhanced ionic conductivity and electrochemical performance.
2. The ionic conductivity of claim 1 dispersed materials improved by 3 orders of magnitude compared to the pure NaNO3 material.
3. The battery of claim 1, demonstrate the enhanced thermal stability, allowing it to operate effectively from 303K to melting point of host.
4. The dielectric constant of claim 1 dispersed materials increased by 100 times as compared to the pure NaNO3 material.
5. Synthesis of claim 1 using homogeneous mixture in the presence of acetone.

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