Initiating Reversible Aqueous Copper–Tellurium Conversion Reaction with High Volumetric Capacity through Electrolyte Engineering

Abstract

Pursuing conversion‐type cathodes with high volumetric capacity that can be used in aqueous environments remains rewarding and challenging. Tellurium (Te) is a promising alternative electrode due to its intrinsic attractive electronic conductivity and high theoretical volumetric capacity yet still to be explored. Herein, the kinetically/thermodynamically co‐dominat copper–tellurium (Cu–Te) alloying phase‐conversion process and corresponding oxidation failure mechanism of tellurium are investigated using in situ synchrotron X‐ray diffraction and comprehensive ex situ characterization techniques. By virtue of the fundamental insights into the tellurium electrode, facile and precise electrolyte engineering (solvated structure modulation or reductive antioxidant addition) is implemented to essentially tackle the dramatic capacity loss in tellurium, affording reversible aqueous Cu–Te conversion reaction with an unprecedented ultrahigh volumetric capacity of up to 3927 mAh cm−3, a flat long discharge plateau (capacity proportion of ≈81%), and an extraordinary level of capacity retention of 80.4% over 2000 cycles at 20 A g−1 of which lifespan thousand‐fold longer than Cu–Te conversion using CuSO4–H2O electrolyte. This work paves a significant avenue for expanding high‐performance conversion‐type cathodes toward energetic aqueous multivalent‐ion batteries.

Deep Multiphase Conversion Derived from NiTe2 Nanosheets with Preferred Kinetics for Highly Reversible Mild Aqueous Zinc–Tellurium Batteries

“…[7][8][9][10] Significant efforts have been made to identify cathodes appropriate for aqueous systems to accommodate zinc ions and embrace more electron transfer, including Mn-oxides, [11][12] V-oxides, [13][14] Prussian blue analogs, [15][16] and transition-metal chalcogenides (TMCs). [9,17] Novel families of electrodes with transformation mechanisms, including chalcogen [18][19][20][21] and halogen, [22] have been established recently and are sought after for their predictable wide range of valence variations. Tellurium (and tellurides) is among the paradigms due to its superior electrical conductivity [7,23] (2 × 10 2 S m −1 , much higher than the homologous sulfur and selenium) and high density (theoretical density ≈6.25 g cm −3 ) for ion storage, which has been revealed to be capable of high-performance cathodes in AZIBs with rather complex multiphase conversion mechanisms that have not yet been clarified.…”

Accumulative Delocalized Mo 4d Electrons to Bound the Volume Expansion and Accelerate Kinetics in Mo6S8 Cathode for High-Performance Aqueous Cu2+ Storage

“…In terms of common wisdom, a dual composite strategy or Janus engineering could provide high-performance electrodes at the lattice structure and bonding structure levels, respectively. − To date, some explorations have been proposed for stable and fast multivalent ion storage, and these strategies involve surface coating, , nanoengineering, − superlattice structure, , heterojunction engineering, , and cathode electrolyte interface (CEI) layers . Lei et al prepared CuS 1– x @PANI heterojunction engineering with high ionic conductivities while alleviating volume expansion, which provides a convenient pathway for electron and ion transport and cycling stability .…”

Ultrahigh‐Speed Aqueous Copper Electrodes Stabilized by Phosphorylated Interphase

“…[9,10] Among the metals that have been utilized as anode materials of rechargeable batteries, [11][12][13][14][15][16][17][18] copper (Cu) is of rising interest due to its distinctive merits, such as stability to water/oxygen, universal redoxion charge-carrier chemistry with multielectron transfer, and the highest density (8.96 g cm −3 ) as well as sub-highest theoretical specific capacity (843 mAh g −1 or 7558 mAh cm −3 , Figure 1a; Table S1, Supporting Information). [19,20] In particular, the preferred reaction potential of Cu (0.34 V vs standard hydrogen electrode (SHE)) implies that it can be employed not only as an anode [21] but also as a cathode in aqueous batteries by matching metals with low potential, [22] such as lead [23] and zinc, [24,25] as was used in the oldest Daniell batteries. However, some critical technical barriers including notorious dendrite growth and irreversible parasitic reactions have persistently plagued copper metal electrodes (CMEs), with the former issue being particularly critical because Cu suffers from worse deposition challenges (Figure 1b) [26,27] and has a higher Young's modulus (E) than zinc (119 vs 108 GPa).…”