Pre‐Lithiated Li₂V₆O₁₃ Cathode Enables High‐Energy Aluminum‐Ion Battery

Abstract

development and manipulation of TMC cathodes with elevated plateau voltages to boost the energy densities of AIBs. More efforts should be devoted into this topic to explore novel cathodes with advantages in both specific capacity and operation voltage.The discharge voltage of intercalation type TMCs is determined by the crystal and electronic structure, elemental composition, and micro-morphology. As discussed in the previous literatures, the ionic character of the chemical bonds between transition metal cations and anions was proposed as an indicator to evaluate the electrochemical potential of cathode. [10] Following this rule, transition metal oxide, in which the highly electronegative oxygen anion would enable the chemical bonds to be more ionic, was predicted to achieve increased plateau voltage. [11] Particularly, vanadium-based oxides have shown the potentiality as high-voltage cathode materials as reported by recent studies, for which porous V 2 O 5 could deliver a relatively high working voltage of ≈0.79 V, and molybdenum-vanadium oxide exhibited a discharge plateau at ≈0.75 V. [12,13] More importantly, the tunable chemical valences of vanadium elements and facile distortion of V-O bonds in vanadium-based oxides provide the possibility to screen more suitable candidates with higher operating voltage by optimizing their crystal structures and electron distributions.Although the reported vanadium-based oxides demonstrated elevated working voltage, their reversible capacities and energy densities were unsatisfied, originating from the strong electrostatic interaction between the inserted Al 3+ and the crystal lattice, which hindered the ionic intercalation and diffusion. [14] Pre-intercalation, as an effective approach, has been successfully employed in various battery systems, especially multivalent-ion batteries, to improve the electrochemical performance of intercalation type electrode materials. [15] The guest ions could expand the interlayer space and shield the electrostatic interaction between charge carriers and the lattice, leading to an accelerated diffusion kinetics. [16,17] Besides, the pre-intercalated ions and molecules could exist as "pillar" to stabilize the framework as well as to reduce the loss of crystallinity, increasing the structural stability of active materials during cycling. [18,19] Nevertheless, the pre-intercalation strategy has not been studied in AIBs so far. It is highly desirable to acquire high-performance vanadium-based oxides for AIBs applications by the attractive pre-intercalation method.Owing to the low-cost, safety, and three-electron redox properties of aluminum, rechargeable aluminum-ion batteries (AIBs) are emerging as a promising energy storage technology. However, exploring suitable cathode material with both elevated working voltage and high reversible capacity remains a daunting challenge. Herein, under the guidance of density functional theory calculations, V 6 O 13 is proposed as a promising cathode candidate in AIBs for the first time. It is demonstrated tha...

Understanding and unlocking the role of V in boosting the reversible hydrogen storage performance of MgH2

“…The high-resolution V 2p X-ray photoelectron spectroscopy (XPS) patterns exhibit that the bimodal peaks at 516.2/523.1 eV and 517.3/524.5 eV (ref. 44 and 45) could be indexed to V 4+ and V 5+ (Fig. 1c), respectively, demonstrating the successful synthesis of V 6 O 13 .…”

Benzoquinone‐Lubricated Intercalation in Manganese Oxide for High‐Capacity and High‐Rate Aqueous Aluminum‐Ion Battery

“…This is because the formation of BQ‐Al 3+ complex weakens the electrostatic field of Al 3+ and extends the interlayer spacing of BQ‐Al x MnO 2 , [ 53,54 ] which substantially boosts intercalation/deintercalation kinetics of Al 3+ . [ 55–58 ] This is demonstrated by the diffusion coefficient of Al 3+ , which is evaluated according to the Randles‐Sevick equation: [ 59,60 ] i p = 2.69 × 10 5 n 3/2 AD 1/2 v 1/2 C 0 , where n is the number of electrons per reaction species, A is the electrode area, D is the diffusion coefficient of Al 3+ , C 0 is the Al 3+ concentration in the electrolyte. Based on the CV measurements (Figure S9, Supporting Information), the diffusion coefficients of Al 3+ in BQ‐Al x MnO 2 are estimated to be ≈2‐fold larger than that in the Al x MnO 2 electrode (Figure S10, Supporting Information).…”

“…This is because the formation of BQ-Al 3+ complex weakens the electrostatic field of Al 3+ and extends the interlayer spacing of BQ-Al x MnO 2 , [53,54] which substantially boosts intercalation/deintercalation kinetics of Al 3+ . [55][56][57][58] This is demonstrated by the diffusion coefficient of Al 3+ , which is evaluated according to the Randles-Sevick equation: [59,60] i p = 2.69 × 10 5 n 3/2 AD 1/2 v 1/2 C 0 , where n is the number of electrons per reaction species, A is the electrode area, D is the diffusion coefficient of Al 3+ , C 0 is the Al 3+ 3a). The distinguished electrochemical behavior of BQ-Al x MnO 2 is further demonstrated by kinetics analysis with an assumption that the current densities (i) of anodic/cathodic peaks obey a power-law relationship with the scan rate (v), namely, i=av b , [61,62] where a is an adjustable parameter, the b value of 0.5 or 1 represents a diffusion-or surface-controlled process.…”

Self‐Discharge Behavior of Graphitic Cathodes for Rechargeable Aluminum Batteries

“…Significant progress has been achieved in the development of RAB cathodes, including those based on carbonaceous materials, [13][14][15][16][17][18][19] oxides, [20][21][22][23] chalcogenides, [24−27] chalcogens, [28][29][30] and organic materials. [31][32][33][34] Oxides and chalcogenides generally exhibit high specific capacities of 200-600 mAh g −1 owing to multielectron redox transitions upon Al 3+ uptake/release.…”