Combining Surface Holistic Ge Coating and Subsurface Mg Doping to Enhance the Electrochemical Performance of LiNi0.8Co0.1Mn0.1O2 Cathodes

Zhaozhe Yu; Qilin Tong; Guiquan Zhao; Guisheng Zhu; Bingbing Tian; Yan Cheng

doi:10.1021/acsami.2c04666

Combining Surface Holistic Ge Coating and Subsurface Mg Doping to Enhance the Electrochemical Performance of LiNi_0.8Co_0.1Mn_0.1O₂ Cathodes

ACS Appl Mater Interfaces. 2022 Jun 8;14(22):25490-25500. doi: 10.1021/acsami.2c04666. Epub 2022 May 24.

Authors

Zhaozhe Yu^{1

2}, Qilin Tong¹, Guiquan Zhao¹, Guisheng Zhu², Bingbing Tian³, Yan Cheng^{1

4}

Affiliations

¹ Guangxi Key Laboratory of Manufacturing Systems and Advanced Manufacturing Technology, Guilin University of Electronic Technology, Guilin 541004, China.
² Engineering Research Center of Electronic Information Materials and Devices, Ministry of Education, Guilin University of Electronic Technology, Guilin 541004, China.
³ International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China.
⁴ College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China.

PMID: 35608938
DOI: 10.1021/acsami.2c04666

Abstract

Nickel-rich layered cathode LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) is the most promising cathode material due to its high specific capacity and lower cost than lithium cobalt oxides. However, NCM811 suffers from structural instability and capacity degradation during charge-discharge cycles. Herein, we report a strategy to construct a conductive network by employing a holistic Ge coating, which interconnects Mg-doped NCM811 particles. Dopant Mg ions, serving as a "pillar" in the Li slab of NCM811, substantially enhance the structural reversibility. The Ge particles are not only coated on the electrode surface but also enter into the electrode pores to form a multidimensional conductive structure, which improves the conductivity of the electrode and slows down the interface side reaction, thus minimizing the irreversible loss of NCM811 upon long cycling. The modified NCM811 electrode delivers a high discharge capacity (∼204 mAh g^-1 at 0.1C), excellent rate performance (∼155 mAh g^-1 at 10C), and high capacity retention (83% after 200 cycles) even at 4.4 V. Additionally, a cylindrical full battery with graphite/modified NCM811 undergoes 1000 cycles with 86% capacity retention at 2C.

Keywords: Mg doping; NCM811 cathode; cyclic stability; lithium-ion batteries; surface holistic Ge coating.