Nanosizing strategy to fabricate uniformly dispersed NiO/Ni/lignin porous carbon composites for high lithium storage

Abstract

Nickel oxide is considered a promising anode material for lithium-ion batteries. Nevertheless, its performance is hindered by significant volume expansion and low electrical conductivity, particularly at larger particle sizes, which lead to a notable decrease in lithium storage capacity and rate performance. To address these challenges, we introduce a nanocomposite strategy to synthesise nickel oxide and lignin-derived porous carbon composites (LPC/Ni/NiO). Through in situ polymerization, lignin macromolecules form a uniform 3D network with nickel carbonate, which, during the subsequent carbonisation process, results in the formation of nickel oxide within a conductive carbon network. This approach reduces the nickel oxide to nanosize and enhances the composite's electrical conductivity, effectively integrating the buffering framework of porous carbon with the high storage capacity of nickel oxide. As a result, the LPC/Ni/NiO composite exhibited significantly improved lithium storage capacity. Notably, when employed as an anode material in lithium-ion half-cells, the optimized composite maintained an excellent specific capacity of 1065 mAh/g after 100 cycles at a current density of 0.2 A/g. It also shown exceptional rate performance, delivering a specific discharge capacity of 505 mAh/g at a current density of 2 A/g, with stable cycling performance. The electrochemical reaction process was further validated using in ex-situ EIS. This study offers valuable insights into scalable synthesis methods for oxide nanocomposites, highlighting their potential as promising anode materials for lithium-ion batteries.