3D printing technology provides a unique platform for rapid prototyping of numerous applications due to its ability to produce low cost 3D printed platforms. Herein, a graphene-based polylactic acid filament (graphene/PLA) has been 3D printed to fabricate a range of 3D disc electrode (3DE) configurations using a conventional RepRap fused deposition moulding (FDM) 3D printer, which requires no further modification/ex-situ curing step. To provide proof-of-concept, these 3D printed electrode architectures are characterised both electrochemically and physicochemically and are advantageously applied as freestanding anodes within Li-ion batteries and as solid-state supercapacitors. These freestanding anodes neglect the requirement for a current collector, thus offering a simplistic and cheaper alternative to traditional Li-ion based setups. Additionally, the ability of these devices’ to electrochemically produce hydrogen via the hydrogen evolution reaction (HER) as an alternative to currently utilised platinum based electrodes (with in electrolysers) is also performed. The 3DE demonstrates an unexpectedly high catalytic activity towards the HER (−0.46 V vs. SCE) upon the 1000th cycle, such potential is the closest observed to the desired value of platinum at (−0.25 V vs. SCE). We subsequently suggest that 3D printing of graphene-based conductive filaments allows for the simple fabrication of energy storage devices with bespoke and conceptual designs to be realised.

Carbon dots inducing petal-like rutile TiO wrapped by ultrathin graphene-rich layers are proposed to fabricate superior anodes for sodium-ion batteries, featuring high-rate capabilities and long-term cyclelife, benefiting from promoted electron transport and a shortened Na diffusion length. High capacities of 144.4 mA h g (at 837.5 mA g ) after 1100 cycles and 74.6 mA h g (at 3350 mA g ) after 4000 cycles are delivered outstandingly.

Oxygen vacancies (OVs) dominate the physical and chemical properties of metal oxides, which play crucial roles in the various fields of applications. Density functional theory calculations show the introduction of OVs in TiO2(B) gives rise to better electrical conductivity and lower energy barrier of sodiation. Here, OVs evoked blue TiO2(B) (termed as B‐TiO2(B)) nanobelts are successfully designed upon the basis of electronically coupled conductive polymers to TiO2, which is confirmed by electron paramagnetic resonance and X‐ray photoelectron spectroscopy. The superiorities of OVs with the aid of carbon encapsulation lead to higher capacity (210.5 mAh g−1 (B‐TiO2(B)) vs 102.7 mAh g−1 (W‐TiO2(B)) at 0.5 C) and remarkable long‐term cyclability (the retention of 94.4% at a high rate of 10 C after 5000 times). In situ X‐ray diffractometer analysis spectra also confirm that an enlarged interlayer spacing stimulated by OVs is beneficial to accommodate insertion and removal of sodium ions to accelerate storage kinetics and preserve its original crystal structure. The work highlights that injecting OVs into metal oxides along with carbon coating is an effective strategy for improving capacity and cyclability performances in other metal oxide based electrochemical energy systems.

Herein, we report a complete additively manufactured (AM) electrochemical sensing platform. In this approach, a fully AM/3D-printed electrochemical system, using a conventional low-cost 3D printer (fused deposition modeling) fabricating both the conductive electrodes and the nonconductive/chemically inert electrochemical cell is reported. The electrodes (working, counter, and pseudo-reference) are AM using a conductive fused-filament comprised of a mixture of carbon black nanoparticles and polylactic acid (CB/PLA). AM components partially coated with silver ink presented a similar behavior to a conventional Ag/AgCl reference electrode. The performance of the AM working electrode was evaluated after a simple and fast polishing procedure on sandpaper and electrochemical activation in a NaOH solution (0.5 mol L–1). Following the electrochemical activation step, a considerable improvement in the electrochemical behavior (current intensity and voltammetric profile) was obtained for model analytes, such as dopamine, hexaammineruthenium­(III) chloride, ferricyanide/ferrocyanide, uric acid, and ascorbic acid. Excellent repeatability (RSD = 0.4%, N = 10) and limit of detection (0.1 μmol L–1) were obtained with the all complete AM electrochemical system for dopamine analysis. The electrochemical performance of the developed system (after simple electrochemical activation of the working electrode) was similar or better than those obtained using commercial glassy carbon and screen-printed carbon electrodes. The results shown here represents a significant advance in AM (3D printing) technology for analytical chemistry.

Mostly reported MoSe2 suffered from easily stacking problem, volume expansion and relative low capacity. From the experience of Li/Na-Se batteries, the exfoliated and encapsulated MoSe2 inside carbon nanospheres with C-O-Mo bonds and large layer distance (0.89 nm) are successfully constructed. This unique effective structure has C-O-Mo bonding allowing high conductivity across the Se-O insulation layer and promoting its reversible conversion. The first-principles calculations demonstrated that the frontier molecular orbitals of C-O-Mo interface structure are mainly localized on the MoSe2 sheet fragment with an appropriate HOMO-LUMO gap (< 4eV),suggesting its good stability and conductivity. Utilized as anodes for LIBs allows a Li-storage capacity to be realized of 1208 mAh g -1 after 150 cycles at 1.0 A g -1 and 519 mAh g -1 after 200 cycles at 4.0 A g -1 . The Na-storage capacity is found to be 543, 491 mAh g -1 after 120 cycles at 0.1, 1.0 A g -1 . Focusing on the analysis of CV, the reducing particle may improve the capacitive behaviors, further resulting the high-rate performance. Ex-situ techniques demonstrated that the emerging Se was constrained uniformly. The controlling of by-product Se plays a key role in achieving a high rate 2 capacity and cycling stability, and opens up a potential avenue for these metal-selenide anodes designs for battery storage systems.

Hierarchical nanoscale carbons have received wide interest as electrode materials for energy storage and conversion due to their fast mass transfer processes, outstanding electronic conductivity, and high stability. Here, heteroatom (S, P, and N) doped hierarchical vesicular carbon (HHVC) materials with a high surface area up to 867.5 m2 g−1 are successfully prepared using a surface polymerization of hexachloro‐cyclotriphosphazene (HCCP) and 4,4′‐sulfonyldiphenol (BPS) on the ZIF‐8 polyhedrons. Significantly, it is the first time to achieve a controllability of the wall thickness for this unique carbon, ranging from 18 to 52 nm. When utilized as anodes for sodium ion batteries, these novel carbon materials exhibit a high specific capacity of 327.2 mAh g−1 at 100 mA g−1 after 100 cycles, which can be attributed to the expanded interlayer distance and enhanced conductivity derived from the doping of heteroatoms. Importantly, a high capacity of 142.6 mAh g−1 can be obtained even at a high current density of 5 A g−1, assigning to fast ion/electronic transmission processes stemming from the unique hierarchical vesicular structure. This work offers a new route for the fabrication/preparation of multi‐heteroatom doped hierarchical vesicular materials.

Screen-printed electrochemical sensing platforms, due to their scales of economy and high reproducibility, can provide a useful approach to translate laboratory-based electrochemistry into the field. An important factor when utilising screen-printed electrodes (SPEs) is the determination of their real electrochemical surface area, which allows for the benchmarking of these SPEs and is an important parameter in quality control. In this paper, we consider the use of cyclic voltammetry and chronocoulometry to allow for the determination of the real electrochemical area of screen-printed electrochemical sensing platforms, highlighting to experimentalists the various parameters that need to be diligently considered and controlled in order to obtain useful measurements of the real electroactive area.

The accurate detection of biological materials has remained at the forefront of scientific research for decades. This includes the detection of molecules, proteins, and bacteria. Biomimetic sensors look to replicate the sensitive and selective mechanisms that are found in biological systems and incorporate these properties into functional sensing platforms. Molecularly imprinted polymers (MIPs) are synthetic receptors that can form high affinity binding sites complementary to the specific analyte of interest. They utilise the shape, size, and functionality to produce sensitive and selective recognition of target analytes. One route of synthesizing MIPs is through electropolymerization, utilising predominantly constant potential methods or cyclic voltammetry. This methodology allows for the formation of a polymer directly onto the surface of a transducer. The thickness, morphology, and topography of the films can be manipulated specifically for each template. Recently, numerous reviews have been published in the production and sensing applications of MIPs; however, there are few reports on the use of electrosynthesized MIPs (eMIPs). The number of publications and citations utilising eMIPs is increasing each year, with a review produced on the topic in 2012. This review will primarily focus on advancements from 2012 in the use of eMIPs in sensing platforms for the detection of biologically relevant materials, including the development of increased polymer layer dimensions for whole bacteria detection and the use of mixed monomer compositions to increase selectivity toward analytes.