Doped Nickelate Electrodes for Sodium-Ion Batteries
Solution Overview
Problem
Sodium-ion batteries face challenges in achieving high initial specific discharge capacity and maintaining charge capacity over multiple cycles due to the formation of undesirable disordered materials and impurity phases like NiO, which affect electrochemical performance.
Innovation Solution
Development of doped nickelate compounds with specific alkali metal compositions, such as NaNi0.5Mn0.25Zr0.25O2 and NaNi0.5Ti0.25Zr0.25O2, which minimize NiO formation and enhance electrochemical stability, along with a method of preparation involving heating precursor materials in a furnace to facilitate solid-state reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NaNi0.5Mn0.5O2 is used as the electrode material, then the material exhibits some reversible charging and discharging ability, but the capacity fades by 25% or more after only 40 cycles
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrode material by introducing dopant elements (Co, Al, Ti, Mg, Fe, Cu, or Zr) at specific concentrations (0.1-0.5 mole ratios) to stabilize the crystal structure and prevent capacity fading during cycling
Solution Approach 2:
The patent creates composite materials by combining multiple elements (Na, Ni, Mn, and dopant elements) in specific ratios to form a multi-element oxide compound that exhibits improved electrochemical stability and reduced capacity loss compared to binary compounds
2Reliability
If lithium-ion battery technology is used, then high energy density and mature technology are achieved, but the cost is high due to expensive lithium sourcing
Solution Approach 1:
The patent changes the alkali metal parameter from lithium to sodium in the electrode material composition, substituting an abundant, low-cost element (sodium) for an expensive, scarce element (lithium) while maintaining similar electrochemical performance characteristics
Solution Approach 2:
The patent employs sodium-based materials that are significantly cheaper than lithium-based materials, using abundant earth-crust elements to reduce manufacturing costs while achieving comparable battery performance for large-scale applications
3Manufacturing precision
If doped nickelate compounds are synthesized through solid-state reactions, then high purity and phase stability are achieved, but the synthesis requires high temperature and long duration
Solution Approach 1:
The patent performs preliminary mixing of precursor materials in specific stoichiometric ratios before heating, ensuring homogeneous distribution of elements that facilitates complete reaction at lower temperatures and reduces synthesis time while maintaining phase purity
Solution Approach 2:
The patent optimizes the heating temperature parameter (reducing from conventional high temperatures) and time parameter (reducing from conventional long durations) by using pre-mixed precursors and controlled atmosphere conditions, achieving the same phase purity in shorter time at lower temperatures
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 doped nickelate compounds exhibit improved electrochemical performance with high initial specific discharge capacity and reduced capacity loss over cycles, making them suitable for energy storage devices like sodium-ion batteries.
Implementation Method 1
a method of preparation involving heating precursor materials in a furnace to facilitate solid-state reactions
Implementation Method 2
both are capable of storing energy, and they both charge and discharge via a similar reaction mechanism
Data Source
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AI summary
The invention relates to novel materials of the formula: A1-deltaNi0.5M1 0.5-xM2 xO2 wherein A comprises one or more alkali metals selected from lithium, sodium and potassium; M1 and M2 each comprise a metal in oxidation state +4 selected from one or more of manganese, titanium and zirconium; further wherein 0 <=delta<=0.1; X is in the range 0 <= X < 0.5; wherein when X = 0 then M1<>Mn or Ti. Such materials are useful, for example, as electrode materials in sodium ion and/or lithium ion and/or potassium ion battery applications.