Black Phosphorus@Ti₃C₂T_x MXene Composites with Engineered Chemical Bonds for Commercial-Level Capacitive Energy Storage

Abstract

Electrolyte-accessibly porous yet densely packed MXene composite electrodes with high ion-accessible surface and rapid ion transport rate have shown exceptional promise for high-volumetric-performance supercapacitors (SCs), but they are largely limited by the insufficient rate capability and poor electrochemical cyclability, in association with the instability in mechanical robustness of the porous network structures. Taking advantage of chemical bonding design, herein a black phosphorus (BP)@MXene compact film of 3D porous network structure is successfully made by in situ growth of BP nanoparticles on crumbled MXene flakes. The strong interfacial interaction (Ti−O−P bonds) formed at the BP− MXene interfaces not only enhances the atomic charge polarization in the BP−MXene heterostructures, leading to efficient interfacial electron transport, but also stabilizes the 3D porous yet dense architecture with much improved mechanical robustness. Consequently, fully packaged SCs using the BP@MXene composite films with a practical-level of mass loading (∼15 mg cm −2 ) deliver a high stack volumetric energy density of 72.6 Wh L −1 , approaching those of lead-acid batteries (50−90 Wh L −1 ), together with a long-term stability (90.58% capacitance retention after 50000 cycles). The achievement of such high energy density bridges the gap between traditional batteries and SCs and represents a timely breakthrough in designing compact electrodes toward commercial-level capacitive energy storage.

Heterogeneous Ni-MOF/V2CTx–MXene hierarchically-porous nanorods for robust and high energy density hybrid supercapacitors

“…3c, a new peak at 530.8 eV assigned to the Ni-O-V bonds can be found in the O 1 s spectra of MOF/MXene/NF-300 composites, similar to the XPS results in related studies. 49,50 The Ni-O-V bonds formed at the interfaces between the MOF and MXene could greatly benet This journal is © The Royal Society of Chemistry 2022 structural stability and interfacial electron transfer during the electrochemical process. 51 Raman spectroscopy was further employed to conrm the existence of interfacial bonds in heterostructured MOF/MXene/ NF-300.…”

“…3c, a new peak at 530.8 eV assigned to the Ni–O–V bonds can be found in the O 1 s spectra of MOF/MXene/NF-300 composites, similar to the XPS results in related studies. 49,50 The Ni–O–V bonds formed at the interfaces between the MOF and MXene could greatly benefit structural stability and interfacial electron transfer during the electrochemical process. 51…”

“Porous and Yet Dense” Electrodes for High‐Volumetric‐Performance Electrochemical Capacitors: Principles, Advances, and Challenges

“…[65g] On the side of rational design of the "porous and yet dense" architectures or to create proper interconnected nanochannels within MXene film electrode, the methods of process optimization (e.g., template-assist and freeze drying) and addition of hetero species (e.g., CNT and graphene) as nanospacer have been developed to further improve their volumetric performance. [128,[130][131][132][133][134][135][136][137][138][139][140][141][142][143][144] For instance, Gogotsi et al used templating with polymethyl methacrylate (PMMA) microspheres to obtain macroporous MXene film electrodes with an open structure (Figure 17e), in which the ion transport lengths were greatly reduced, leading to an exceptional high-rate performance and an acceptable volumetric performance. [128] Freeze drying is a useful method to dry out the particular material while maintaining its looseness.…”

Double-core–shell polysaccharide polymer networks for highly flexible, safe, and durable supercapacitors

“…With the booming of smart cities, sustainable energy supply devices, such as rechargeable batteries [1][2][3][4] and supercapacitors, [5][6][7][8][9] are rapidly upgrading and updating in our daily life. However, these devices are currently made with cumbersome construction and low exibility, which make it difficult for them to meet the application needs of wearable and portable microdevices, such as intelligent robots, articial e-skin, mobile sensors, health monitoring systems and smart clothes.…”