Electrochemical Energy Storage Applications Research Articles

High-Entropy Engineering of Cubic SiP with Metallic Conductivity for Fast and Durable Li-Ion Batteries.

A cost-effective, scalable ball milling process is employed to synthesize the InGeSiP3 compound with a cubic ZnS structure, aiming to address the sluggish reaction kinetics of Si-based anodes for Lithium-ion batteries. Experimental measurements and first-principles calculations confirm that the synthesized InGeSiP3 exhibits significantly higher electronic conductivity, larger Li-ion diffusivity, and greater tolerance to volume change than its parent phases InGe (or Si)P2 or In (or Ge, or Si)P. These improvements stem from its elevated configurational entropy. Multiple characterizations validate that InGeSiP3 undergoes a reversible Li-storage mechanism that involves intercalation, followed by conversion and alloy reactions, resulting in a reversible capacity of 1733mAhg-1 with an initial Coulombic efficiency of 90%. Moreover, the InGeSiP3-based electrodes exhibit exceptional cycling stability, retaining an 1121mAhg-1 capacity with a retention rate of ≈87% after 1500 cycles at 2000mAg-1 and remarkable high-rate capability, achieving 882mAhg-1 at 10 000mAg-1. Inspired by the distinctive characteristic of high entropy, the synthesis is extended to high entropy GaCu (or Zn)InGeSiP5, CuZnInGeSiP5, GaCuZnInGeSiP6, InGeSiP2S (or Se), and InGeSiPSSe. This endeavor overcomes the immiscibility of different metals and non-metals, paving the way for the electrochemical energy storage application of high-entropy silicon-phosphides.

High-performance asymmetric supercapacitors assembled with novel disc-like MnCo2O4 microstructures as advanced cathode material

Herein, porous MnCo2O4 with disc-like (MnCo2O4-discs) and ring-like (MnCo2O4-rings) microstructures were respectively synthesized using an initial hydrothermal method at different temperatures and a calcination treatment in air. The electrochemical properties of these MnCo2O4 materials were investigated in three-electrode and two-electrode systems, and as such, MnCo2O4 presented a battery-like electrochemical response. The specific capacity of MnCo2O4-discs was determined to be 296.1C/g at 1 A/g, superior to 246.3C/g for MnCo2O4-rings. An asymmetric supercapacitor (ASC) was assembled with MnCo2O4 as the cathode and activated carbon (AC) as the anode to evaluate the potential for practical application. The MnCo2O4-discs//AC ASC exhibited an energy density (Ed) of 35.8 W h kg−1 at a power density (Pd) of 927.5 W kg−1. For the MnCo2O4-rings//AC ASC, an inferior Ed of 31.4 W h kg−1 under 890.9 W kg−1 was achieved. Furthermore, the two ASCs presented outstanding cyclic performance after 5000 cycles at 6 A/g. The exceptional properties of MnCo2O4 microstructures can be applied to the assembly of ASC devices, which can have promising potential for application in electrochemical energy storage. This synthetic method is straightforward, cost-effective, and can be extended to fabricate similar electrode materials with superior electrochemical performance.

Engineering sulfur defective Bi2S3@C with remarkably enhanced electrochemical kinetics of lithium-ion batteries

Introducing the appropriate vacancies to augment the active sites and improve the electrochemical kinetics while maintaining high cyclability is a major challenge for its widespread application in electrochemical energy storage. Here, core–shell structured Bi2S3@C with sulfur vacancies was prepared by hydrothermal method and one-step carbonization/sulfuration process, which significantly improves the intrinsic electrical conductivity and ion transport efficiency of Bi2S3. Additionally, the uniform protective carbon layer around surface of composite maintains structural stability and effectively alleviates volume expansion during alloying/dealloying. As a result, the BSC-500 anode exhibits a brilliant reversible capacity of 636 mAh/g at 0.2 A/g and a long-term stable capacity of 524 mAh/g for 500 cycles at a high current density of 3 A/g in lithium-ion batteries. In addition, the assembled Bi2S3@C//LiCoO2 full cell delivered a capacity of 184 mAh/g at 1 A/g and excellent cyclability (125 mAh/g after 1000 cycles). The proposed strategy of combining sulfur vacancies with a core–shell structure to improve the electrochemical kinetics of Bi2S3 in lithium-ion batteries off the prospect for practical applications of transition metal sulfide anodes.

Large-Scale Synthesis of Highly Porous CuO/Cu2O/Cu/Carbon Derived from Aerogels for Lithium-Ion Battery Anodes.

In this work, an effective strategy for the large-scale fabrication of highly porous CuO/Cu2O/Cu/carbon (P-Cu-C) has been established. Cu-cross-linked aerogels were first continuously prepared using a continuous flow mode to form uniform beads, which were transformed into P-Cu-C with a subsequent pyrolysis process. Various pyrolysis temperatures were used to form a series of P-Cu-C including P-Cu-C-250, P-Cu-C-200, P-Cu-C-350, and P-Cu-C-450 to investigate suitable pyrolysis conversion processes. The obtained P-Cu-C series were utilized as anodes of lithium-ion batteries, in which P-Cu-C-250 exhibited a higher reversible gravimetric capacity, excellent rate capability, and superior cycle stability. The enhanced behavior of P-Cu-C-250 was benefitted from the synergistic interaction between uniformly dispersed CuO, Cu2O, Cu nanoparticles, and highly graphitized carbon with a large surface area and highly porous structure. More importantly, the preparation of P-Cu-C-250 could be scaled up by taking advantage of the continuous flow synthesis mode, which may provide pilot- or industrial-scale applications. The large-scale fabrication proposed here may give a universal method to fabricate highly porous metal oxide-carbon anode materials for electrochemical energy conversion and storage applications. Porous CuO/Cu2O/Cu/carbon derived from Cu-crosslinked aerogels was used as Li-ion battery anode materials, exhibiting a high reversible areal capacity, large gravimetric capacity, superior cycling performance, and excellent rate capacity. A continuous preparation method is established to ensure the product scaled up.

Superior supercapacitor performance with tuneable 2D/3D morphological microporous carbons of zeolitic imidazolate frameworks synthesized by recycling mother liquors

Carbonized metal–organic frameworks (MOFs)-based nanoporous carbon materials (NPCs) offer attractive activities in electrochemical energy conversion and storage (EECS) applications; however, there is the need for scalable MOFs production under reduced energy/environmental impact. This study reports a green synthesis route for model zeolitic imidazolate framework (ZIF-8) materials via recycling methanol-based mother liquors (ZIF-RMLx) under room temperature stirring and their carbonized materials (CZC-RMLx) for high-performance supercapacitors. Series of ZIF-RMLx samples produced in four recycles offer rod-/sheet-/polyhedral-like 2D/3D microstructures with tuneable internal and external framework and morphological features. Accordingly, CZC-RMLx, obtained by direct pyrolysis, with high microporosity and surface area of 1500 m2 g−1 deliver excellent capacitance values of 200–340 F g−1, compared to typical MOFs-derived or chemically activated/templated NPCs, produced via extended chemical processing. Structure-relevant and comparative performance analysis reveal insights for improved charge storage and carbonization-dependent graphitization, nitrogen-doping and microporosity-controlled capacitance characteristics in the CZC-RMLx over typical NPCs in literature. The device-level performance with a long-term durability over 21,000 cycles is demonstrated. The practical potential of CZC-RMLx is further evaluated by fabricating solid-state cells and their parallel and series circuit combinations result in overall capacitance and voltage boost to 450 F g−1 and 2.4 V, respectively.

Nitrogen and oxygen self-doped hierarchical porous carbon nanosheets derived from turmeric leaves for high-performance supercapacitor

It is a formidable challenge to develop efficient and low-cost nanostructured carbonaceous materials for electrochemical energy storage application. Herein, a hierarchical porous carbon nanosheet is successfully synthesized in a facile manner from turmeric leaves by a two-step chemical activation strategy using KOH activator. The biomass-derived interconnected two-dimensional (2D) carbon framework prepared at 900 °C presents high self-doped N (11.42 at%) and O contents (7.77 at%) together with specific surface area and pore volume of 541 m2/g and 0.47 cm3 g−1, respectively. Consequently, the resultant electroactive functional material shows a specific capacitance of 389 and 310 F/g at a current density of 1 A/g in acidic and neutral electrolytes, respectively. Additionally, an assembled symmetric supercapacitor device in Na2SO4 electrolyte delivers good capacitance retention of 90 % after 5000 consecutive charge–discharge cycles along with high specific energy (39.44 Wh kg−1at specific power of 0.49 kW kg−1). This work provides a cost-effective, eco-friendly and sustainable outlook to prepare high-valued porous carbons from reliable biomass sources for high-performance supercapacitor application.

Electrochemical performance of NiS/r-GO composite-based electrode material for electrochemical energy storage application

Electrochemical performance of NiS/r-GO composite-based electrode material for electrochemical energy storage application

Synthesis of graphene-quantum-dots decorated metal-free carbon nitride for effective electrocatalysts in redox-mediated electrolyte

Defect engineering of N/C3N4 two-dimensional material provides an efficient way to tune the electronic structures and make more active sites for electrocatalysis, which is attractive for electrochemical energy storage applications. Other than modification of heteroatoms on the top of C3N4 two-dimensional material as a photosensitizer, electrolyte design is very desirable to enrich the research area and provides a wide range of choices for diverse applications. Herein, the graphene quantum dots (GQDs) decorated N doped g-C3N4 electrocatalysts for water splitting were fabricated, which exhibited enhanced electron transfer efficiency, better electrocatalytic performance, and long-term stability. The electrochemical performances of GQDs@C3N4+x in neutral, acidic, alkaline, and redox-mediated electrolytes were investigated, respectively. The GQDs@C3N4+x electrode displays excellent activity toward electrocatalytic reaction in redox-mediated solution. The increase in electrocatalytic performance could be attributed to the reaction of redox species with the surface holes and the defects of GQDs@C3N4+x, leading to a better separation of the excited electron-hole pairs. Thus, this work greatly broadens the application prospects of carbon nitrogen complex by rational defect engineering and electrolyte regulation.

Enhanced electrochemical energy storage devices utilizing a one-dimensional (1D) α-MnO2 nanocomposite encased in onion-like carbon

AbstractThis work describes the fabrication of a novel one-dimensional (1D) α-MnO2 nanorods encased in onion-like carbon (or) carbon nano-onions (OLC) via microwave irradiation techniques employing electrolytic manganese dioxide (EMD), which is especially beneficial for rapid ion and electron transfer, and great structural stability. The composite of α-MnO2 and OLC demonstrates exceptional performance as an electrode across various electrochemical energy storage systems, including zinc-ion batteries (ZIB), sodium-ion batteries (SIB), and supercapacitors (SC) than the pristine α-MnO2. In SIB systems, the composite exhibits a specific capacity of 266 mAh g−1 at initial cycle with 50% capacity retention over 500 cycles, whereas the pristine electrode delivers only 39% capacity retention. The rapid yet controlled charge transfer kinetics facilitated by OLC addition in the α-MnO2 matrix outperforms as the ZIB cathode with an excellent specific capacity of 476 mAh g−1 with 100% capacity retention, while the pristine sample exhibits 77.5% capacity retention. As a SC electrode, the α-MnO2/OLC composite exhibits better electrochemical properties such as rectangular behavior, increased specific capacitance (792 F g−1), excellent capacity retention at high current densities, and others. The higher surface area that could be offered by the OLC to the α-MnO2 matrix facilitates the improved electrochemistry in the pristine sample and this kind of modification can be a viable solution to overcome the limitations of α-MnO2 for electrochemical energy storage applications. It is important to note that the performance outputs of α-MnO2/OLC composite are far better than the regular carbon (graphite, graphene) in α-MnO2 electrodes. Further, OLC provided with high surface area and ordered morphology can play the role of conductivity booster, structural stabilizer, and electrochemical active material in all the energy storage applications which may give a significant research attention in near future.

Confined grotthuss proton-conduction along polyoxometalate chains inside carbon nanotubes for high-rate charge storage

Redox-active materials with excellent rate capability and cycling performance are in highly demand for electrochemical energy storage and conversion applications. Here, we unveil the confined proton-conduction behavior of one-dimensional polyoxometalate chains inside single-walled carbon nanotubes (SWNTs). The polyoxometalate molecules including phosphomolybdic acid {HPMo} and phosphotungstic acid {HPW} are encapsulated within SWNTs via host–guest recognition, driven by the electron transfer from nanotubes to polyoxometalates. Impressively, the redox hybrids of polyoxometalate@SWNTs deliver abnormal rate performance in acidic solution with capacity retentions over 73 % at high sweep rate of 1000 mV s−1, relative to the capacity at 10 mV s−1. This value is comparable to that of the pure SWNTs, typically known as double-layer capacitive materials. Electrochemical analyses reveal the Grotthuss proton-conduction mechanism of {HPMo} in SWNTs with a low activation energy of 0.11 eV. Therefore, the {HPMo}@SWNT hybrid demonstrates quasi diffusion-free characteristic with dominant capacitive contribution over 60 % at different sweep rates. Molecular dynamic simulations and density functional theory calculations evidence the strong burst-like transport of protons in the {HPMo}@SWNT hybrid. This process is dynamically favored in the continuous and long-range hydrogen-bond network along polyoxometalate chains with bound/free water molecules inside SWNTs. The superiority of nanoconfined Grotthuss mechanism may engender an exciting avenue for developing high-performance energy storage materials.

Self-supported iron-doped nickel oxide multifunctional electrodes for highly efficient energy storage and overall water-splitting uses

Caused by complex synthesis processes, slow diffusion rates, and the formation of undesired nanostructures, it is tedious to produce a high-quality nickel oxide (NiO) electrodes for potential energy storage and water splitting applications. This paper introduces a novel chemical technique for producing self-supported iron-doped NiO electrodes having a high concentration of oxygen vacancies by utilizing different iron-based salts i.e. iron nitrate, iron chloride, iron ammonium sulfate, iron fumarate, and iron sulfate salts. After examining physical properties, the electrochemical energy storage and water splitting measurements were performed where iron nitrate precursor-mediated self-supporting Fe-NiO electrode confirms the optimum performance. Specifically, it exhibits a specific capacitance (SC) of 3302.5 Fg−1 at a current density of 5 Ag−1. The as-fabricated Fe-NiO-A//Bi2O3 asymmetric supercapacitor has a broad voltage range of 1.5 V, a remarkable volumetric-energy-density of 98.2 W hkg−1 at a power density of 900 Wkg−1, and a long-lasting cycling life with 92.6 % capacity retention after 5000 cycles at a current density of 15 Ag−1. A bifunctional Fe-NiO//Fe-NiO electrocatalyst demonstrates a current density of 10 mA cm−2 and remarkable long-term durability of 75 h without any degradation while operating at an ultra-low cell voltage of only 1.51 V, specifying importance of self-supported Fe-doped NiO electrodes for electrochemical energy storage and water splitting applications.

NiMnCo-LDH in-situ derived from ZIF-67@ZnO as self-supporting electrode for asymmetric supercapacitor device

Metal-organic frameworks have attracted much attention due to their abundant redox sites and tunable characteristics, which are advantageous for energy storage applications. However, the low electrical conductivity, poor physical strength and undesirable capacity seriously hinder their applications. Therefore, designing effective and convenient strategies to build composites with unique structures will be of practical significance. Herein, we successfully generate NMC-LDH/ZnO@CC nanocomposites by growing ortho-hexagonal nickel–cobalt layered double hydroxide (NMC-LDH) nanosheets in-situ on ZIF-67 precursor covering vertical arrays of ZnO nanorods. As a result of the unqiue ortho-hexagonal structure, highly ordered arrangement of active substances and multi-dimensional spaces of the prepared NMC-LDH/ZnO@CC binder-free electrode, its capacitance is as high as 9258 mF cm−2 at a current density of 2 mA cm−2 and the capacitance retention is maintained at 87.5 % after 5000 cycles. Furthermore, in order to explore the practical value of the prepared binder-free electrode, the NMC-LDH/ZnO@CC//AC solid-state asymmetric supercapacitor device is assembled. The energy density of the assembled supercapacitor is 24.6 W h kg−1 at a power density of 170 W kg−1 and 1020 W kg−1 at an energy density of 11.8 W h kg−1. In addition, a versatile instrument for monitoring air humidity, time and ambient temperature in portable environments can be powered by a single ultracapacitor unit for more than 30 min. Overall, this study provides a unique strategy for synthesizing ZIF derivatives with novel morphologies for electrochemical energy storage applications.

One-pot synthesis of phosphorous, iodine atoms co-functionalized graphene for high-performance supercapacitor and flame-retardant applications

There has been extensive research on heteroatom-doped graphene for electrochemical energy storage and flame-retardant (FR) applications. Herein, we used a one-pot method for developing phosphorous, iodine co-doped reduced graphene oxide (PI@rGO) from red phosphorus and iodine via in situ graphene oxide (GO) reduction for supercapacitor and FR applications. In a symmetrical two-electrode cell device, the as-prepared PI@rGO demonstrated good super capacitive performance of 178 F g−1 at a current density of 1.0 A g−1, along with an exceptional energy density of 20 Wh kg−1 and power density of 1791 W kg−1. The as-synthesized PI@rGO demonstrated outstanding cyclic stability at a high current density of 10 A g−1, retaining up to 84 % of its initial capacitance after more than 6000 recurrent charge–discharge cycles. The synthesized PI@rGO showed excellent FR properties toward cotton fabric and sustained cotton fabric up to 337 s with continuous flame exposure. The control cotton fabric was completely burned in 16 s. The synthesized PI@rGO coated cotton fabric showed an excellent value of 39 % limiting oxygen index and residual char length of 2 cm. With the excellent super capacitive performance and FR properties, PI@rGO can be a promising candidate for different applications including supercapacitors and FR products.

Nano Metal–Organic Frameworks as Advanced Electrode Materials in Electrochemical Energy Storage

AbstractNano metal–organic frameworks as an attractive new class of porous materials, are synthesized via metal ions and organic ligands. With their desirable properties of abundant pores, high specific surface areas, fully exposed active sites and controllable structures, nano MOFs are acknowledged to be one of the most vital materials in electrochemical energy storages. However, in their practical applications, nano MOFs are still confronted with various difficulties and challenges because of their low conductivity, poor stability, and other disadvantages. The selection and development of MOF composites, MOF–derived materials and modified MOFs might be beneficial to use as better electrode materials to greatly improve the electrochemical properties of energy storage devices. This paper mainly focuses on the recent developments of nano MOFs as prospective materials in electrochemical energy storage applications, including lithium–ion batteries (LIB), lithium–sulfur batteries (LSB), zinc–ion batteries (ZIB), and supercapacitors (SCs). Finally, the challenges faced by these kinds of energy storage devices are proposed, along with the current directions and prospect.

Synergistic enhancement of electrochemical supercapacitor efficiency via Co3O4/GO composite electrode

Abstract In recent times, the convergence of metal oxide adorned graphene oxide (GO) composites has ignited substantial notice, driven by their potential to revolutionize electrochemical energy storage applications, particularly in the realm of supercapacitors. This surge in attention is attributable to the harmonious amalgamation of metal oxide nanoparticles with the versatile GO sheets, resulting in intricately nanostructured materials. The present investigation the synthesis of hybrid done by hydrothermal route, yielding nanostructured Co3O4/GO. Extensive electrochemical assessment reveals a pinnacle specific capacitance of 786.69 F/g at 1 mA/cm2 current density within a 3 mol L−1 KOH aqueous medium, accompanied by commendable rate-handling capabilities.

Sustainable Synthesis of Porous Biomass-Derived Carbon from Tecoma capensis for High Performance Supercapacitors: Characterization and Electrochemical Evaluation

Biowaste carbon products possess interesting physico-chemical properties and are cost-effective due to their remarkable characteristics. Biomass carbon derived from Tecoma capensis (TCL) was processed using pyrolysis at a controlled temperature in an eco-friendly, innovative and sustainable way to develop biomass-derived carbon material. The aim of this study is to demonstrate the facile synthesis of porous carbon compounds from biowaste and evaluate their use in supercapacitors. Various analytical methods, such as structural analysis, morphological studies and electrochemical studies, have been employed to characterize the carbon material generated from biomass. Electrochemical performance evaluation was conducted through cyclic voltammetry and galvanostatic charge-discharge studies utilizing 1 M H2SO4 and 1 M KOH aqueous electrolyte, which exhibited a specific capacitance of 238 F g-1. The outcomes of the studies suggested that the eco-friendly, straightforward process can be utilized to prepare biomass carbon for the electrochemical energy storage applications in an efficient and sustainable manner.

One dimensional WS2 nanoarchitectures coupled with g-C3N4 anchored rGO sheets for high performance electrochemical energy storage applications

Herein, tungsten sulfide (WS2) nanorods (NRs) with g-C3N4 and rGO were synthesized in order to design a cost-effective electrode material (WS2/g-C3N4/rGO) for advanced electrochemical relevance. The rGO nanosheets along with a metal free g-C3N4 with graphene like layered structure improved the electrical conductivity and electro-active surface area of the ternary nanocomposite. The structure, morphology and surface area of as-prepared electrodes were comprehensively studied via XRD, FTIR, EDX, FESEM and BET analyses. As projected, surface assisted WS2 NRs were smooth, uniform, interconnected and well aligned with an average diameter of 24.78 nm diameter. The ternary nanocomposite (WS2/g-C3N4/rGO) delivered highest specific capacitance 1383.33F/g at a scan rate 5 mV/s. The GCD plots proposed large discharge time for WS2/g-C3N4/rGO nanocomposite (918 sec) with high specific capacitance of 850 mAh/g at 1 A/g as compared to WS2/g-C3N4 (623 sec) with specific capacitance 578 mAh/g. The energy density and power density of WS2/g-C3N4/rGO nanocomposite were calculated to be 35.41 Wh/Kg and 139.15 W/Kg, respectively. The noteworthy electrochemical efficiency of WS2/g-C3N4/rGO nanocomposite noticed from CV and GCD results are attributed to the enhanced surface area, porous nanoarchitecture, and nanocomposite composition. The ternary nanocomposite electrode (WS2/g-C3N4/rGO) also showed the fastest ion diffusion and good capacitive retention. In conclusion, our prepared nanocomposite electrode material (WS2/g-C3N4/rGO) exhibits good electrochemical performance and can serve as a better option in the field of energy storage devices.

Fabrication of new Mn-based MXene structure from MnO2 for electrochemical energy storage applications

MXene compound of Mn7C3 was successfully prepared using combined mechanical, thermal, and leaching processes. A mixture of MnO2, Al, and black C with stoichiometric ratios 3:5:2 was mechanically activated in the ball mill for 5 h. Thermal treatment at 1000 °C was applied to this mixture. Magnetic separation was used to separate Mn3AlC2 from Al2O3. After that, Al was leached from Mn3AlC2 using 15% HF. SEM investigation indicated the formation of Mxene (Mn7C3) particles as aligned sheet-like structure and particle size distribution range of 110–145 nm. The obtained MXene compounds were used as an active material vs. lithium metal and assembled in a coin cell. The electrochemical assessment of this cell was carried out using galvanostatic cycling, electrochemical impedance spectroscopy, and cyclic voltammetry techniques. MXene (Mn7C3) cell showed better performance with charge capacity by preserving about 150 mAh g−1 after 100 cycles. The coulombic efficiency of the cell is approaching 99.2% after long cycles.Graphical abstract

Electrochemical energy storage application of MOF-derived porous NiO thin films synthesized by solvothermal route

Metal oxides are the most suitable materials for supercapacitors because of their strong electrical characteristics and cheap prices. Owing to its large surface area, controlled pore structure, uniformity, the metal-organic frameworks are employed as inventive material for electrodes in the field of energy storage. In this report, Ni-MOFs have been prepared on conducting stainless steel substrates using a solvothermal technique with different Ni concentrations. Further, these films were annealed at 350 °C for getting NiO phase. The crystalline nature of MOF-derived NiO is confirmed by XRD. The surface morphology of the films has been studied with FE-SEM, showing a nanosheet-like structure. Consequently, electrochemical tests on NiO electrodes were performed in 1 M KOH with a potential window of -0.2–0.5 V. The NiO electrode deposited with 0.3 M concentration delivers a specific capacity of 680 C g−1 at a current density of 0.5 mA cm−2, an energy density of 22.40 Wh kg−1 at a power density of 2.4 kW kg−1 and good cyclic performance with 96% retention after 5000 cycles. The synthesized MOF derived NiO showed excellent specific capacity and good cycle stability due to their large surface area, porous and more durable structure. Hence, the synthesis approach designated here may provide an efficient way to develop MOF-derived NiO for effective supercapacitor applications.

Tuning the Microenvironment of Water Confined in Ti3C2Tx MXene by Cation Intercalation.

The local microenvironment has recently been found to play a major role in the electrocatalytic activity of nanomaterials. Modulating the microenvironment by adding alkali metal cations into the electrolyte can be used to either suppress hydrogen or oxygen evolution, thereby extending the electrochemical window of energy storage systems, or to tune the selectivity of electrocatalysts. MXenes are a large family of two-dimensional transition metal carbides, nitrides, and carbonitrides that have shown potential for use in electrochemical energy storage applications. Due to their negatively charged surfaces, MXenes can accommodate cations and water molecules between the layers. Nevertheless, the nature of the aqueous microenvironment in the MXene interlayer space is poorly understood. Here, we apply Fourier transform infrared spectroscopy (FTIR) to probe the hydrogen bonding of intercalated water in Ti3C2Tx as a function of intercalated cation and relative humidity. Substantial changes in the FTIR spectra after cation exchange demonstrate that the hydrogen bonding of water molecules confined between the MXene layers is strongly cation-dependent. Furthermore, the IR absorbance of the confined water correlates with resistivity estimated by 4-point probe measurements and interlayer distance calculated from XRD patterns. This work demonstrates that cation intercalation strongly modulates the confined microenvironment, which can be used to tune the activity or selectivity of electrochemical reactions in the interlayer space of MXenes in the future.