Hybrid Solid-State Battery Electrolyte for Low-Temperature Densification
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Solution Overview
Problem
The development of lithium-ion batteries is hindered by safety hazards from flammable organic liquid electrolytes, and existing all-solid-state batteries face challenges in achieving high ion conductivity and stability due to high-temperature sintering processes.
Innovation Solution
A hybrid all-solid-state secondary battery is developed using a combination of oxide-based and sulfide-based solid electrolytes, doped with graphene quantum dots, and synthesized through plasma heat treatment and pulsed laser annealing at low temperatures, enhancing ion conductivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If high-temperature sintering is used to obtain dense pellets, then density is improved, but phase stability deteriorates due to lithium loss
Solution Approach 1:
The patent changes the temperature parameter from conventional high-temperature sintering (900-1100°C) to low-temperature sintering (600-800°C), achieving dense pellets while maintaining phase stability. This parameter change resolves the contradiction by finding an optimal temperature window that provides sufficient densification without causing lithium loss and phase degradation.
Solution Approach 2:
The patent uses composite materials including lithium lanthanum zirconium oxide (LLZO) with aluminum doping, combined with other oxides and sulfides to create a multi-component solid electrolyte system. This composite approach enhances both density and phase stability simultaneously, as the multiple components work synergistically to maintain structural integrity at lower sintering temperatures.
2Reliability
If conventional sintering methods are used, then processing simplicity is maintained, but ion conductivity is insufficient
Solution Approach 1:
The patent applies preliminary actions by pre-mixing precursors using wet chemical methods (sol-gel or co-precipitation) to create uniformly distributed composite powders before sintering. This preliminary preparation ensures homogeneous composition and promotes better densification and ion conductivity at lower temperatures, resolving the contradiction between improved performance and process complexity.
Solution Approach 2:
The patent replaces conventional mechanical/thermal sintering with a combination of wet chemical synthesis followed by low-temperature sintering. This substitution of the sintering mechanism allows achieving high ion conductivity (10^-4 S/cm) at lower temperatures with shorter times, compensating for the added chemical processing steps.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The hybrid battery achieves high lithium ion conductivity (1×10−4 to 9×10−3 S/cm) and capacity retention of 96.9% after 500 cycles, suitable for electric vehicles and IT products, with a low-cost, high-density production process.
Implementation Method 1
Since a temperature and pressure are simultaneously applied in a plasma heat treatment method (e.g., spark plasma sintering (SPS))
Implementation Method 2
spark plasma sintering (SPS)
Implementation Method 3
pulsed laser annealing technology used in the present disclosure
Data Source
AI summary
A solid electrolyte includes an oxide solid electrolyte layer, and a sulfide solid electrolyte layer, and the oxide solid electrolyte layer and the sulfide solid electrolyte layer are doped with graphene quantum dots (GQDs).