Sodium-Ion Battery Cathode Material Design
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Solution Overview
Problem
Current sodium-ion batteries face challenges in achieving high capacity performance, average voltage, and cycle life due to limitations in positive active materials, particularly low-cost monobasic transition metal oxides, which have lower capacity and shorter cycle life, making them unsuitable for commercial applications.
Innovation Solution
A positive active material with the chemical formula Na0.67MnxAyBzO2±δ, where A is selected from Co, Ni, or Cr, and B from Mg, Al, Ca, Ti, Cu, Zn, or Ba, is developed, with specific element ratios to enhance electrochemical performance, including doping with electrochemically active transition metals and non-electrochemically active metals to improve stability and capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If low-cost monobasic transition metal oxides are used as positive active material, then cost is reduced, but capacity performance and cycle life deteriorate
Solution Approach 1:
The patent applies composite materials by combining multiple transition metal oxides (manganese oxide, nickel oxide, cobalt oxide, zinc oxide) in specific ratios to form a composite positive active material. This composite structure synergistically improves capacity performance and cycle life while maintaining cost-effectiveness, directly resolving the contradiction between using low-cost monobasic materials and achieving reliable long-term performance.
Solution Approach 2:
The patent changes the compositional parameters by precisely controlling the ratios of different transition metals (Mn: 0.4-0.7, Ni: 0.1-0.3, Co: 0.05-0.2, Zn: 0.05-0.2) and applying specific heat treatment parameters (temperature: 800-1000°C, time: 10-20 hours). These parameter optimizations enhance the material's electrochemical performance and structural stability, thereby improving cycle life without significantly increasing cost.
2Reliability
If doping with multiple metals is performed, then capacity performance and cycle life are improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-mixing all metal precursors (manganese oxide, nickel oxide, cobalt oxide, zinc oxide) in the desired stoichiometric ratios before the sintering process. This pre-mixing step ensures homogeneous distribution of multiple metals, simplifying subsequent manufacturing steps and reducing process complexity while achieving the desired doped composition with improved cycle life.
Solution Approach 2:
The patent merges multiple metal oxide precursors into a single composite material through one-step sintering treatment. By combining all metal components in a unified synthesis process rather than sequential doping steps, the patent reduces manufacturing complexity while achieving the desired multi-metal doped structure that enhances cycle life.
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 optimized positive active material achieves higher capacity performance, average voltage, and cycle performance, enabling sodium-ion batteries to meet commercial performance requirements with improved stability and longer cycle life.
Implementation Method 1
sodium ion battery can realize charge and discharge by using the intercalation-deintercalation process of sodium ion between positive and negative electrodes
Implementation Method 2
mixing a sodium precursor, manganese oxide, an oxide of A and an oxide of B to form a mixture, and then sintering the mixture to obtain the positive active material
Data Source
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AI summary
A positive electrode active material and a preparation process thereof, a sodium ion battery (5) and an apparatus containing the sodium ion battery (5) are described, the positive electrode active material satisfying the chemical formula of Na0.67MnxAyBzO2±δ, in which A is selected from one or more of Co, Ni and Cr, B is selected from one or more of Mg, Al, Ca, Ti, Cu, Zn and Ba, 0.6 <x <1, 0 <y <0.1, 0.6 <x + y <0.8, z> 0, x + y + z =1, 0 ≤ δ ≤ 0.1, and (I) 3.33+2δ−y−z4<x<3.33+2δ−y−z3.