Nanotechnology Nanotechnology 35 (2024) 472001 (73pp) https://doi.org/10.1088/1361-6528/ad690b Topical Review ‘Beyond Li-ion technology’—a status review Arghya Narayan Banerjee ∗  and Sang Woo Joo ∗  School of Mechanical and IT Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea E-mail: arghya@ynu.ac.kr, banerjee_arghya@hotmail.com and swjoo@yu.ac.kr Received 20 February 2024, revised 12 July 2024 Accepted for publication 30 July 2024 Published 4 September 2024 Abstract Li-ion battery is currently considered to be the most proven technology for energy storage systems when it comes to the overall combination of energy, power, cyclability and cost. However, there are continuous expectations for cost reduction in large-scale applications, especially in electric vehicles and grids, alongside growing concerns over safety, availability of natural resources for lithium, and environmental remediation. Therefore, industry and academia have consequently shifted their focus towards ‘beyond Li-ion technologies’. In this respect, other non-Li-based alkali-ion/polyvalent-ion batteries, non-Li-based all solid-state batteries, fluoride-ion/ammonium-ion batteries, redox-flow batteries, sand batteries and hydrogen fuel cells etc. are becoming potential cost-effective alternatives. While there has been notable swift advancement across various materials, chemistries, architectures, and applications in this field, a comprehensive overview encompassing high-energy ‘beyond Li-ion’ technologies, along with considerations of commercial viability, is currently lacking. Therefore, in this review article, a rationalized approach is adopted to identify notable ‘post-Li’ candidates. Their pros and cons are comprehensively presented by discussing the fundamental principles in terms of material characteristics, relevant chemistries, and architectural developments that make a good high-energy ‘beyond Li’ storage system. Furthermore, a concise summary outlining the primary challenges of each system is provided, alongside the potential strategies being implemented to mitigate these issues. Additionally, the extent to which these strategies have positively influenced the performance of these ‘post-Li’ technologies is discussed. Supplementary material for this article is available online Keywords: beyond-LIB, Na-ion battery, polyvalent-ion battery, redox-flow battery, all-solid-state battery, hydrogen fuel cell, hydrogen economy Contents 1. Introduction 2 2. Issues related to LIB technology 6 2.1. Battery abuses and safety 6 2.2. Cost reduction vs. innovation limit 7 2.3. Resources: access, depletion, sustainability 8 3. Na/K-based batteries 10 ∗ Authors to whom any correspondence should be addressed. 3.1. NIB/KIBs: promises 11 3.2. NIB/KIBs: challenges and opportunities 11 3.2.1. Basic working principle 11 3.2.2. Half-cell vs. full-cell 11 3.2.3. Cathode materials 13 3.2.4. Anode materials 21 3.3. Na/K ASSB 22 3.4. Na/K—S/Se battery 25 3.4.1. Na/K—S battery 25 3.4.2. Na/K-Se battery 25 1 © 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.