BiNi Solid-State Electrode Structure for Stable Battery Cycling
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Solution Overview
Problem
Lithium secondary batteries face issues with low charge-discharge efficiency and deteriorated cycle characteristics due to lithium dendrite deposition and expansion/contraction of alloy electrodes, leading to poor capacity retention and current collecting properties.
Innovation Solution
A battery design featuring a first electrode with a current collector and an active material layer containing BiNi with a crystal structure of space group C2/m, paired with a solid electrolyte layer to prevent electrolyte intrusion and maintain electron conduction paths during charge-discharge cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If alloy materials (Bi, Si, Sn) are used as electrode active materials to increase capacity, then charge-discharge capacity is improved, but lithium dendrite deposition occurs and cycle characteristics deteriorate
Solution Approach 1:
The patent uses BiNi intermetallic compound as a composite material combining bismuth (which alloys with lithium) and nickel (which provides structural stability). This composite structure allows the material to maintain high capacity through lithium alloying while the nickel component prevents dendrite formation and maintains structural integrity during cycling, thus resolving the contradiction between capacity and cycle life.
Solution Approach 2:
The patent changes the crystal structure parameter by specifying BiNi with space group C2/m, which has specific atomic arrangement that balances lithium alloying capability with structural stability. This parameter change in crystal structure enables the material to achieve both high capacity retention and good cycle characteristics by controlling the way lithium atoms insert and extract from the BiNi lattice.
2Quantity of substance
If alloy electrode materials are used to increase capacity, then energy storage is improved, but expansion and contraction during charging and discharging leads to poor capacity retention
Solution Approach 1:
The BiNi intermetallic compound functions as a composite material where the Bi component provides high lithium alloying capacity while the Ni component provides structural framework stability. During charging and discharging, the Ni-rich structure accommodates the expansion and contraction of Bi during lithium insertion/extraction, maintaining overall structural integrity and preventing capacity fade, thus resolving the contradiction between energy storage and capacity retention.
Solution Approach 2:
The patent specifies the crystal structure parameter (space group C2/m) which determines the unit cell dimensions and atomic positions. This parameter change enables the crystal structure to undergo reversible volume changes during lithium alloying while maintaining structural coherence, allowing the material to achieve both high energy storage capacity and stable capacity retention over multiple cycles.
3Use of energy by moving object
If traditional liquid electrolytes are used, then ion conduction is achieved, but electrolyte intrusion into active material causes capacity decrease
Solution Approach 1:
The patent changes the physical state parameter of the electrolyte from liquid to solid. Solid electrolytes have fixed structure that prevents them from penetrating into the active material pores, eliminating the capacity degradation caused by electrolyte intrusion. At the same time, the solid electrolyte maintains adequate ionic conductivity through its crystal lattice structure, thus resolving the contradiction between ion conduction and capacity stability.
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 battery achieves improved cycle characteristics with greater than 50% initial discharge capacity retention after 50 cycles and reduced capacity decrease, maintaining high efficiency and capacity over repeated charging and discharging.
Implementation Method 1
lithium secondary batteries that use electrodes containing aluminum, silicon, tin, or the like that electrochemically alloys with lithium during charging
Implementation Method 2
a solid electrolyte layer disposed between the first electrode and the second electrode
Data Source
AI summary
A battery includes a first electrode, a second electrode, and a solid electrolyte layer disposed between the first electrode and the second electrode, the first electrode includes a current collector and an active material layer disposed between the current collector and the solid electrolyte layer, the active material layer contains BiNi, and the BiNi has a crystal structure of space group C2/m.