Anionic Activity in Fast-Charging Batteries: Recent Advances, Prospects, and Challenges

Abstract

The increasing demand for fast-charging batteries to expedite the widespread adoption of electric vehicles calls for continual improvements of the anode materials to confer high energy and power densities. However, the fundamental limitations of the mainstream graphite and Li-metal anodes for fast-charging applications include the capacity fading and safety issues mainly caused by the Li plating, as well as the sluggish transport kinetics at large current densities. Recently, great attention has been paid to the emergence of large-capacity anodes by tailoring the bonding covalency to modulate the electronic structure and alter the insertion voltage for boosting fast-charging ability and suppressing metal plating. Development of new fast-charging materials by tailoring anionic activity allows us to better understand the key aspects of the bond covalency and band positioning for cation/anion doping and interface/ surface engineering. This Review provides an overview of the recent advances in the development of fast-charging anodes around tuning the bonding covalency by bimetal modulation; alloying hard and soft anions to alter the electronic structure and metal plating voltage; constructing anion-derived interfacial films; and surface substituting the ordered terminal groups. Furthermore, we highlight the practical limits of capacity fading at large current densities and describe potential strategies of anionic redox in phosphides and interfacial energy storage of conversion-type anodes to offer additional capacities. We also discuss the prospects for the commercial adoption of high-performance anodes containing various elements to rival the prevalent graphite or Li anodes for fast-charging applications.

Reinforcing CoO Covalency via Ce(4f)─O(2p)─Co(3d) Gradient Orbital Coupling for High‐Efficiency Oxygen Evolution

“…[41][42][43] As for the theoretical correction, the Mott-Hubbard effect illustrates the band splitting of (M-O)* into the filled lower Hubbard band (LHB) and empty upper Hubbard band respectively by considering the strong on-site d-d Coulomb and exchange interaction U (Figure 1b). [21,44,45] The bandgap between the M-O and (M-O)* bands is called the charge-transfer energy (Δ), which is dependent on the electronegativity between M and O, and the Madelung potential. [46,47] Note that U is inversely related to the orbital volume and valence state of the d-metal species, and the disparity between U and Δ may create the difference in the contribution of 3d electrons close to E F , which displays the potential in modulating M-O covalency.…”

Quasi‐Topological Intercalation Mechanism of Bi0.67NbS2 Enabling 100 C Fast‐Charging for Sodium‐Ion Batteries

“…Given substantial progress in frameworktype SIB cathodes with outstanding rate performance, [4,5] simultaneous research on high-rate matching anodes is essential to enabling the widespread application of high-performance SIBs. [6][7][8][9][10][11][12][13][14] Bismuth (Bi) has attracted considerable attention among various candidates of anode materials owing to its high volumetric capacity (3750 mAh cm −3 ) and moderate reaction potential (0.6 V vs. Na + /Na). [15][16][17] In addition, Bi has a narrow bandgap and high ionic conductivity that benefits Na + diffusion.…”

“…From the molecular point of view, the activity of chemical reactions originates from the weak bonding interactions and possible migratory behavior of atoms. [35][36][37] Comparatively, the intercalation-type electrode materials with strong metal-anion bonding undergo a bonding strength decrease rather than bond breakage during ion insertion, [6,38] which resists deformation under stress and maintains a stable framework when incorporated with active components. [39][40][41] Moreover, 2D intercalation host frameworks with high electrical conductivity have been proven to not only buffer volume expansion of alloying metal but also greatly improve rate performance.…”

Intercalative Motifs‐Induced Space Confinement and Bonding Covalency Enhancement Enable Ultrafast and Large Sodium Storage

“…Given substantial developments in high‐performance SIB cathodes with kinetically favorable Na + storage channels, [ 7–9 ] the simultaneous exploration of advanced anodes to confer high capacities and rate capabilities is crucial to enabling the widespread application of SIBs. [ 10–17 ] Among various anode candidates, bismuth sulfide (Bi 2 S 3 ) with a unique layered structure has attracted considerable attention due to the high theoretical gravimetric capacity (625 mAh g −1 ), high volumetric capacity (4250 mAh cm −3 ), and low cost. [ 18–21 ] Nevertheless, the advantages are overshadowed by the inferior cycling and rate performance due to the continuous aggregation and pulverization of Bi caused by the large volume expansion (≈244%) during sodiation process.…”