ZHOU Xiaoliang ^{1, 2}, GUO Weilin ¹, LIU Limin ^{1, 2}, ZHANG Shuo ¹, WEN Kun ¹

(1. College of Chemical Engineering, Southwest Petroleum University, Chengdu 610500, Sichuan, China;

2. Tianfu Yongxing Laboratory, Chengdu 610500, Sichuan, China)

Extended abstract:[Significance] Sodium-ion batteries (SIBs), as an emerging sustainable energy storage technology, hold strategic significance in multiple aspects. Their abundant, widely distributed raw materials and low cost reduce reliance on scarce lithium resources, enhancing energy security. SIBs also offer unique advantages in safety, cycle life and operating temperature range, with a higher thermal runaway temperature than lithium batteries and stable charge/discharge in low temperatures. Additionally, their lower manufacturing costs and broad application prospects in large-scale energy storage and electric vehicles make them a promising technology. The development of SIBs is not only a technological advancement but also a response to global energy transition and sustainable development. The traditional energy system, heavily dependent on fossil fuels, faces challenges such as resource scarcity, environmental pollution and climate change. SIBs, with their unique advantages, can play a significant role in constructing a clean, low-carbon, safe and efficient energy system. They can be used in renewable energy storage, smart grids and electric vehicles, promoting the transformation of the energy system towards sustainability. Moreover, the rise of SIBs reflects the innovation and exploration in the field of energy storage. They have broad application prospects in various fields. In large-scale energy storage, SIBs can be used for grid-connected energy storage, peak shaving and frequency modulation and renewable energy storage. In the field of electric vehicles, SIBs can be applied in pure electric vehicles, hybrid electric vehicles and commercial vehicles. In addition, they can also be used in consumer electronics, aerospace and other fields.[Progress] In recent years, significant progress has been made in SIB. Aiming at the difficulties of the electrolyte/sodium metal interface in all-solid-state SIB, the research progress in reducing the interfacial impedance and improving the interfacial contact through material optimization, interfacial chemical regulation, interfacial structural regulation, interfacial layer construction and heat treatment, is summarized, by taking the Na/Na₃Zr₂Si₂PO₁₂ interface as an example. Interfacial material optimization focuses on the development, design and optimization of electrolyte and electrode materials to improve the performance and stability of the interface. By regulating the structure, composition and surface properties of the materials, the ion transport rate can be increased, the interfacial resistance can be reduced and the interfacial side reactions can be suppressed. The reaction behavior of the interface between inorganic solid electrolyte and electrode can be optimized by regulating the chemical environment of the interface, i.e., the stability of the interface can be improved, the interfacial resistance can be reduced, and the electrolyte loss can be suppressed by adding interfacial modifier, controlling the interfacial redox state and regulating the interfacial charge density. By regulating the structural characteristics of the interface to improve the interfacial properties, i.e., by controlling the morphology, thickness, porosity, etc. of the interfacial layer, one can optimize the ion and electron transport paths, reduce the interfacial impedance and improve the energy storage and release rate. By making full use of the surface modification of various materials to construct interfacial interlayers, the buffer interlayer usually plays two key roles in the Na/NZSP interface, both as a filler for the voids and defects on the NZSP surface, which can connect the SSEs to the Na metal anode to regulate the Na⁺ ion transport and reduce the interfacial resistance, while serving as a protective layer to prevent the occurrence of the Na and SSEs in the long term cyclic process of the side reactions. Heat treatment is a common method for interface improvement, which can promote the increase in interfacial bonding strength, crystallization and mutual diffusion of interfacial particles, thus improving the electrochemical properties and stability of the interface, through high-temperature sintering, thermal annealing and other heat treatment processes.[Conclusions and prospects] In summary, SIBs show great potential in terms of resource utilization, safety and cost control, but still face challenges in terms of energy density and interfacial stability. Future research should focus on optimizing electrolyte/electrode interfacial compatibility, as well as further improving battery energy density and cycle life, so as to accelerate its commercialization in all-solid-state sodium-ion batteries and contribute more to the development of sustainable energy storage field. With the advancement of technology and the maturity of the industrial chain, SIBs are expected to be widely used in large-scale energy storage and electric vehicles, and make greater contributions to the development of sustainable energy storage.

Key words: ceramic electrolyte; interface modification; sodium battery; Na₃Zr₂Si₂PO₁₂