The role of nickel (Ni) as a critical metal in clean energy transition: applications, global distribution and occurrences, production-demand and phytomining.

[Display omitted] • Increasing demand for Ni in the clean energy transition has identified Ni as a critical metal. • Ni provides high storage capacity, which reduces the size of lithium ion-batteries. • High-grade Ni laterites and sulfide deposits are depleting due to intensive production and overconsumption. • Exploitation of low-grade Ni sources such as serpentine soil will contribute to maintain a sustainable supply in future. • Phytomining is a potential route for economic exploitation of Ni from low-grade sources. In 2022, nickel (Ni) was nominated as a critical metal due to its wide applications in the metal industry, especially in clean energy applications to achieve climate mitigation targets. Meantime, rapid industrialization and escalating demand for electronic battery manufacturing have increased global Ni consumption, and therefore available primary Ni resources will not be sufficient to cater to the demand. As a result, currently, the Ni supply chain is diversifying focusing on low-grade Ni resources which were previously considered as economically invaluable. This paper presents comprehensive study on different applications of Ni, existing high-grade Ni resources, mode of occurrence, and the production and future demand of Ni, and discusses the state of art on the different leaching and extraction methods to recover Ni from low-grade sources, such as mine tailings, galvanic sludge, electronic batteries, and serpentine soil. In addition, this paper highlights the current status of the Ni phytomining approaches in serpentine soil and its future perspectives. It is evident that a development of Ni phytomining industry as a carbon–neutral mining technique is essential to overcome Ni supply risk for the commercial production of Ni using low-grade resources. Finally, this study will evaluate the production of high-quality Ni from low-grade secondary sources. [ABSTRACT FROM AUTHOR]