Thick cathode technology developed for next-generation high-performance lithium metal secondary batteries

Study by Prof. Yun Young-soo’s team published in international journal Advanced Fiber Materials

▲ (From left) Professor Yun Young-soo (corresponding author, KU-KIST Graduate School of Converging Science and Technology), Kang Dong-hyuk (first author, integrated master-doctoral degree program),  

Park Min-hyuck (co-first author, integrated master-doctoral degree program), Lee Jeong-hun (co-first author, research professor)

The research team led by Professor Yun Young-soo from the Department of Integrative Energy Engineering has developed a thick cathode technology to increase the energy density of lithium metal secondary batteries.

The results of this study were published online on December 12, 2023, in the international journal Advanced Fiber Materials (IF: 16.1, top 1.7%).
* Title of paper: High-Performance Thick Cathode Based on Polyhydroxyalkanoate Binder for Li Metal Batteries.

The thick cathode technology aimed at increasing the electrode density of lithium secondary batteries overcomes the energy limitations without altering the conventional cathode materials used in lithium secondary batteries. However, the typical slurry method used in electrode manufacturing poses challenges such as cracking and flaking during the production of thick electrodes. Additionally, it leads to increased charge transfer resistance and local current overload, resulting in severe technical limitations such as a compromised rate capability and poor cycling stability.

In this study, a high-performance thick electrode was manufactured using a dual-network combination strategy based on a conductive nanofibrillar network (CNN) and a nano-bridging amorphous polyhydroxyalkanoate (aPHA) binder. The CNN and aPHA dual network demonstrated ease of thick cathode manufacture (≥250 μm thickness and ≥90 wt.% active cathode material) through a mass-producible slurry method, while exhibiting a high rate capability and excellent cycling stability.

Furthermore, the combination of the thick cathode and thin Li metal anode pair (Li//t-NCM) demonstrated optimal energy performance, providing a high-performance lithium metal battery with a high energy density of ~25.3 mW cm−2, an output density of ~1,720 W L−1, and an outstanding specific energy of ~470 W h kg−1 at 6 mA h cm−2.

<Figure 1>

▲ Figure description : Schematic of the thick electrode created using the dual-network combination strategy, and a diagram comparing the functional roles of the conductive network and binder