Solid-state lithium metal battery negative electrode interface stabilization technology and fast charging solution

Abstract

The invention provides a solid-state lithium metal battery negative electrode interface stabilization technology and a fast charging solution. A gradient three-dimensional conductive network-solid electrolyte composite interface layer is constructed on the surface of the negative electrode, and a dynamic ion transmission channel is formed by combining in-situ polymerization, so that the growth of lithium dendrites is inhibited, and the interface impedance is reduced. Meanwhile, by adopting a self-adaptive fast charging strategy, based on a battery SOC-temperature-rate dynamic model, and through a gradient pulse current and voltage compensation algorithm, the capacity is charged to 80% within 10 minutes, the cycle life breaks through 5000 times, and the capacity retention ratio is larger than or equal to 90%. The scheme considers high specific energy, long service life and safety, and is suitable for the fields of electric automobiles, consumer electronics and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy batteries, focusing on the anode interface engineering and fast charging technology of solid-state lithium metal batteries. Aiming at the risks of lithium dendrite penetration, interfacial side reactions and thermal runaway, a solid electrolyte-anode interface collaborative optimization scheme is provided, which is adapted to high-rate charge and discharge conditions, and promotes the commercialization of the next generation of high specific energy batteries. Background Art

[0002] In traditional lithium metal batteries, the disordered growth of lithium dendrites on the anode interface easily causes short circuits. The interfacial impedance of solid electrolytes is high, and fast charging is likely to lead to thermal runaway. Existing technologies are difficult to achieve both high specific energy (>500 Wh / kg) and long life (cycle >2000 times). There is an urgent need for collaborative innovation in interface structure and charging strategies to break through the bottleneck. Summary of the Invention

[0003] The present invention constructs a dynamic ion buffer layer and a mechanical confinement framework on the anode surface through a three-dimensional gradient doping-in-situ film formation composite technology to inhibit the directional deposition of lithium dendrites. At the same time, an adaptive stepped pulse-temperature and pressure coupling fast charging algorithm is developed to achieve charging to 85% in 8 minutes at a rate of 10C without lithium deposition, and the cycle life is increased by 300%.

Claims

1. A solid-state lithium metal battery anode interface stabilization technology, characterized in that: Construct a lithiated metal oxide (Li x MOy, M = Zr / Ti)-three-dimensional carbon-based framework composite layer (thickness 20 ± 5 nm, porosity 55-60%) on the surface of the negative electrode to achieve uniform deposition of lithium ions and physical barrier to dendrites.

2. The fast charging solution adopts an adaptive pulse-temperature and voltage dual-control protocol, dynamically adjusts the pulse current (8-10C) and the intermittent duration (1:2-1:3) based on the battery internal resistance (R≤10Ω) and the surface temperature (T≤48℃), and suppresses lithium plating and thermal runaway.

3. Battery performance limitations: the negative electrode interface impedance ≤ 3.5Ω·cm², the Coulomb efficiency ≥ 99.0% after 1000 cycles, and there is no short-circuit failure under the 10C fast charging condition, and the volume expansion rate ≤ 1.0%.