Understanding of Sodium Storage Mechanism in Hard Carbons: Ongoing Development under Debate

Abstract

depleting Li resources. While Li shortage may not be incurred in the immediate future, the increasingly depleting resources will challenge the long-term scale-up industrial development of LIBs. Besides lithium, cobalt, which has been used in several commercial cathode materials, is facing a more serious resource depletion risk. [6][7][8] The high cost of extraction and the uneasy availability generate large price fluctuations imposing serious market stability risk. The infancy of recycling technology with immature secondary alternative has motivated researchers to explore new EES technologies. [9][10][11][12][13] Here, sodium-ion batteries (SIBs) have recently emerged as a promising alternative energy storage technology to LIBs due to the similar mechanism and potentially low cost. [14][15][16] Unlike Li, sodium (Na) are resources abundant, low cost, more globally available, and can be obtained from minerals and brine. [17,18] As for other constituents, many of the SIBs cathodes are configured to iron (Fe) as in iron phosphate or iron cyanide, and the use of aluminum foil instead of copper foils as anode current collector can lead to even more substantial cost savings. [19][20][21][22] The cost-effective precursor, i.e., Na and battery constituents, recognizes SIBs as a more economically viable choice compared to its Li-counterpart. [23,24] Therefore, SIBs are regarded as promising candidates of LIBs for large-scale energy storage application, which is a key step in developing sustainable renewable energy systems. [25] The cycle life, cost, and safety features are among the few major concerns for stationary batteries installed in a large-scale energy storage system. Thus, resource-abundancy, structure-stability, low-cost, and nontoxicity of the electrode materials are highly desirable to ensure the efficient and sustainable working of these large-scale battery systems with minimum maintenance.However, the intrinsic dissimilarities between Li and Na in terms of their ion radius (0.76 Å for Na + vs 1.02 Å for Li + ) and electrochemical potential (2.71 V vs SHE for Na + ; 3.04 V vs SHE for Li + ), result in some inconsistencies between SIBs and LIBs techniques. [26,27] The much larger ion size of Na presents a major challenge for configuring electrode materials with high Na-storage capacity and fast ion transport, especially for the anode material. [28][29][30][31] Among the various materials, carbon-based materials are considered as promising commercial anodes due to their excellent structural stability, nontoxicity, and low cost. [32][33][34][35][36] Unfortunately, graphite has been proven to Hard carbons are promising anode candidates for sodium-ion batteries due to their excellent Na-storage performance, abundant resources, and low cost. Despite the recent advances in hard carbons, the interpretation of the Na-storage mechanism in hard carbons remains unclear, with discrepancies over a general model describing the corresponding structure-property relationship. For the rational structural design of high-performan...

Biomass-Derived Hard Carbon with Interlayer Spacing Optimization toward Ultrastable Na-Ion Storage

“…Although the sodium storage behavior of hard carbon is largely explored, it is still controversial due to the complexity of microstructure. − In order to better understand the nature of sodium storage of FHC-1300, in situ Raman spectroscopy technique is applied to monitor the texture evolution of local microstructure during a complete cycle. As shown in Figure a, the G band gradually shifts toward lower wavenumbers upon discharging in the plateau region.…”

Doping Regulation in Polyanionic Compounds for Advanced Sodium‐Ion Batteries

“…[3,4] In this context, room temperature sodium-ion batteries (SIBs), which are similar to LIBs in electrochemical characteristics and working mechanisms, emerge as a promising technology for grid-scale energy storage because of the wide abundance in the earth's crust and low cost of sodium resources. [5][6][7][8][9][10] In the past decades, tremendous efforts have been made in exploring appropriate electrode materials for SIBs, such as transition metal oxides, [11][12][13][14][15] phosphates, [16][17][18][19] ferrocyanides, [9,20,21] metal alloys, [22][23][24][25] hard carbon, [26][27][28][29][30][31][32][33][34] and chalcogenides, [35][36][37][38][39][40][41] and some of them have shown acceptable electrochemical performance. What's more, a lot of reviews have summarized recent developments in electrode materials for SIBs.…”

Conformal carbon nitride thin film inter-active interphase heterojunction with sustainable carbon enhancing sodium storage performance

“…10, 3 challenges. 16,17 An innovative approach for improving the sodium storage performance of disordered carbons relies on a post-synthetic process that introduces an artificial interphase to the surface of the active material or a dopant to tune the electronic structure. [18][19][20][21][22][23] Here, the material requirements are different from the ones of electrode (storage) materials.…”

“…Therefore, selecting appropriate precursors and post-modications are fundamental steps to control the carbons' chemical and structural properties while reducing the processing challenges. 16,17 An innovative approach for improving the sodium storage performance of disordered carbons relies on post-synthetic processing to deposit an articial interphase on the active material's surface or a doping agent to tune the electronic structure. [18][19][20][21][22][23] Here, the material requirements are different from the ones of electrode (storage) materials.…”