MXene‐Ti₃C₂ Armored Layer for Aluminum Current Collector Enable Stable High‐Voltage Lithium‐Ion Battery

Abstract

considerable electrochemical stability, which is ascribed to the natural passivation layer Al 2 O 3 . [10] The Al 2 O 3 layer could availably prevent Al from corrosion in an ideal state (absence of water, voltage <4.0 V versus Li/Li + approximately). [11][12][13] Obviously, it is hardly to achieve an anhydrous environment and corresponding strategies are adopted to deal with the aluminum oxidation after passivation layer breakdown. Modulating electrolyte composition is effective, including additives, [14,15] superconcentrated electrolytes [16,17] or new lithium salts [18,19] and solvents. [20,21] And recently, the modification of Al current collector has gradually attracted scientific attention, such as in situ chemical conversion [22,23] or passivation layer assembly. [24][25][26] An advanced artificial passivation layer we anticipate should simultaneously resist corrosion and conduct electricity. In addition, the power and energy trade-off of LIBs restricts the thickness of artificial passivation layer. [27] Naturally, designing a suitable Al current collector is challenging and meaningful.MXene (Ti 3 C 2 T x ) nanosheets, as a member of 2D transition metal carbides, own extraordinary conductivity, abundant adjustable functional groups (OH, O, or F) and unique layered structure, [28][29][30][31] which are frequently employed as active material or conductive substrate to construct nanocomposite electrodes. [32] Furthermore, MXene also possesses a foundation for anticorrosion (high strength, modulus, and chemical stability). In inorganic system, MXene is requisitioned as a combined physical barrier enhancer to metal protection. [33][34][35] Consequently, the better electrochemical stability of MXene in organic environment makes it an innovative perspective to protect Al current collector solely in high-voltage LIBs. Herein, for the first time, an MXene armored layer was fabricated on pure Al current collector (MXene-Al) via a simple self-assembly procedure, which is homogeneous and ultrathin (<100 nm), protecting Al matrix in LiPF 6 -carbonates electrolyte without compromising conductivity. In Li||LiCo 1/3 Ni 1/3 Mn 1/3 O 2 (NCM333) system with a high cut-off voltage of 4.5 V, cells with MXene-Al possess an enhanced electrochemical performance. The discharge capacity retention reaches up to 81.4% after 300 cycles at 0.5 C, while that of pristine Al is only 21%. The self-discharge propensity is alleviative and rate/power performance is improved. Elevating operating voltage (above 4.5 V) is a consequential approach to increasing the energy density of lithium-ion batteries (LIBs). Unfortunately, the corrosion of cathode aluminum (Al) current collector at high voltage limits the application of high-voltage LIBs. In this report, for the first time, MXene-Ti 3 C 2 T x nanosheets are proposed as an armored layer for Al current collector to conquer the corrosion under high operating voltage over 4.5 V versus Li + /Li. The MXene armored layer is fabricated via a self-assembly procedure, which exhibits ultra-thinness le...

MXene‐Based Current Collectors for Advanced Rechargeable Batteries

“…Coating way may cause uneven distribution. Other ways like the Langmuir Blodgett scooping method, [ 95 ] are too complex to be suitable for large‐scale preparations. Through different post‐processing modes, MXene can exist in solid powder or disperse in water.…”

“…d) Cycling properties of NCM333/MXene─Al, NCM333/C‐Al, NCM333/Al cell at 0.5 C under high cut‐off voltage of 4.5 V. Reproduced with permission. [ 95 ] Copyright 2022, Wiley‐VCH. e) Illustration of fabrication of Si/MXene (Ti 3 C 2 T X ) film.…”

“…First, MXene solution was fabricated by HCl/LiF method. Then, commercial spherical silicon powders were added to as-prepared MXene suspension and stirred for 6 h. After vacuum filtration and [95] Copyright 2022, Wiley-VCH. e) Illustration of fabrication of Si/MXene (Ti 3 C 2 T X ) film.…”

“…Copyright 2019, American Chemical Society. Reproduced with permission [95]. Copyright 2022, Wiley-VCH.…”

“…b,c) SEM images of Al and MXene─Al. d) Cycling properties of NCM333/MXene─Al, NCM333/C-Al, NCM333/Al cell at 0.5 C under high cut-off voltage of 4.5 V. Reproduced with permission [95]. Copyright 2022, Wiley-VCH.…”