Long‐Cycle‐Life Cathode Materials for  Sodium‐Ion Batteries toward Large‐Scale Energy Storage Systems

Abstract

The development of large-scale energy storage systems (ESSs) aimed at application in renewable electricity sources and in smart grids is expected to address energy shortage and environmental issues. Sodium-ion batteries (SIBs) exhibit remarkable potential for large-scale ESSs because of the high richness and accessibility of sodium reserves. Using low-cost and abundant elements in cathodes with long cycling stability is preferable for lowering expenses on cathodes. Many investigated cathodes for SIBs are dogged by structural and morphology changes, unstable interphases between the cathode and the electrolyte, and air sensitivity, causing unsatisfactory cycling performance. Therefore, understanding the mechanism of capacity degeneration in depth and developing precise solutions are critical for designing low-cost cathodes that are highly stable under cycling. Herein, recent progress in long-cycle-life and low-cost cathodes for SIBs is focused on, and a comprehensive discussion of the key points in SIBs toward large-scale applications is provided. The roots of the unstable cycling performance of low-cost cathodes are discussed. Also, effective strategies are summarized from the recent progress on long-cycle-life and low-cost cathodes. This review is expected to encourage deeper investigation of long-lifespan cathodes for SIBs, particularly for potential large-scale industrialization.

The Distance Between Phosphate‐Based Polyanionic Compounds and Their Practical Application For Sodium‐Ion Batteries

“…Therefore, considering the trade-off between cost and performance, some low-cost phosphate-based polyanionic cathodes, such as Fe/Mn-based phosphates, are expected to be applied in the large-scale energy storage system with ultra-long cycle life. [215]…”

High-entropy prussian blue analogs with 3D confinement effect for long-life sodium-ion batteries

“…2 Therefore, it is urgent to develop high-performance sodium storage materials for sodium ion batteries. Different from polyanionic compounds and layered oxides, [3][4][5][6] Prussian blue analogs (PBAs) (Na 2−x M[Fe(CN) 6 ] 1−y ,y$nH 2 O, M = Fe, Mn, Co, Ni, Cu, etc., , = [Fe(CN) 6 ] vacancies) offer high theoretical specic capacity and three-dimensional open framework for fast Na + diffusion. 7,8 Moreover, the convenient and cost-effective synthesis process, specically the co-precipitation method, makes PBAs one of the most promising cathode materials for commercial sodium-ion batteries (SIBs).…”

“…2 Therefore, it is urgent to develop high-performance sodium storage materials for sodium ion batteries. Different from polyanionic compounds and layered oxides, 3–6 Prussian blue analogs (PBAs) (Na 2− x M[Fe(CN) 6 ] 1− y □ y · n H 2 O, M = Fe, Mn, Co, Ni, Cu, etc. , □ = [Fe(CN) 6 ] vacancies) offer high theoretical specific capacity and three-dimensional open framework for fast Na + diffusion.…”

Electronic States Tailoring and Pinning Effect Boost High-Power Sodium-Ion Storage of Oriented Hollow P2-Type Cathode Materials

“…Layered sodium transition metal oxides (Na x TMO 2 , 0 < x ≤ 1), as the main cathode materials of SIBs, represent high theoretical capacities, flexible crystal structures, scalable synthesis process, and abundantly available transition metals. − According to the coordination environment of Na + and different stacking of oxygen layers, P2-type cathodes are given more expectation for scale development originating from more open prismatic paths for Na + transport with promising rate capability. − Meanwhile, their high tolerances against moist air will definitely reduce the difficulty of the preparation and storage . For the Na 2/3 Ni 1/3 Mn 2/3 O 2 cathode, typically, all Na + (2/3) can be reversibly extracted with a high specific capacity (161 mAh g –1 ) based on the Ni 2+ /Ni 3+ /Ni 4+ redox reaction in the voltage window of 2–4.5 V. However, unsatisfied P2–O2 phase transition associated with abrupt change (about 23.2%) in the length of the c -axis and oxygen framework shift when charging to 4.2 V, remarkably reduces the diffusion coefficient of Na + , slows down the transport kinetics and breaks down the cycle stability. − Moreover, the adverse TM slab sliding combined with structural changes leads to increased internal stress and collapsed layered structure with severe cracks.…”