Production method for electrochemically stable anode particulates for lithium secondary batteries

Abstract

Provided is a method of producing multiple anode particulates, comprising: a) dispersing an electrically conducting material, primary particles of an anode active material, an optional electron-conducting material, and a sacrificial material in a liquid medium to form a precursor mixture; b) forming the precursor mixture into droplets and drying the droplets; and c) removing the sacrificial material or thermally converting the sacrificial material into a carbon material to obtain multiple particulates, wherein a particulate comprises one or a plurality of anode active material particles having a volume Va, an electron-conducting material, and pores having a volume Vp which are encapsulated by a thin encapsulating layer having a thickness from 1 nm to 10 μm and a lithium ion conductivity from 10−8 S / cm to 5×10−2 S / cm and the volume ratio Vp / Va in the particulate is from 0.3 / 1.0 to 5.0 / 1.0.

Description

[0001]The present invention relates generally to the field of rechargeable lithium battery and, more particularly, to the anode active materials in the form of particulates secondary particles containing a core of anode active material primary particles and pores encapsulated by a thin shell (a thin encapsulating layer) containing a carbonaceous or graphitic material and a method of producing same.BACKGROUND OF THE INVENTION[0002]A unit cell or building block of a lithium-ion battery is typically composed of an anode current collector, an anode or negative electrode layer (containing an anode active material responsible for storing lithium therein, a conductive additive, and a resin binder), an electrolyte and porous separator, a cathode or positive electrode layer (containing a cathode active material responsible for storing lithium therein, a conductive additive, and a resin binder), and a separate cathode current collector. The electrolyte is in ionic contact with both the anode ...

AI Technical Summary

Benefits of technology

The patent text describes a method for improving the performance of lithium batteries. The method involves using a thin layer of particulate material made of graphene sheets, which are placed between the anode and the electrolyte of the battery. This layer of particulate helps to accommodate the volume expansion of the anode material during charging, while also reducing the formation and destruction of a solid-electrolyte interface (SEI) phase. By controlling the volume expansion of the particulate, the battery has a longer life and can charge and discharge more times without losing capacity. The method also involves operating the battery in a way that prevents the anode from being at a high electrochemical potential during the initial charge cycles. This results in a more stable surface for the battery and further improves its performance.

Problems solved by technology

We have discovered that this strategy surprisingly results in significantly reduced battery capacity decay rate and dramatically increased charge / discharge cycle numbers.

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