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This Interface article is based on presentations at the 242nd ECS Meeting in Atlanta, in the centennial symposium “E04 - 100 Years of the Electrodeposition Division: Past, Present, and Future,” given on Wednesday October 12, 2022.

For a battery module where single cells are connected in series, the single cells should each have a similar state of charge (SOC) to prevent them from being exposed to an overcharge or over-discharge during charge–discharge cycling. To detect the existence of unbalanced SOC cells in a battery module, we propose a simple measurement method using a single-frequency response of electrochemical impedance spectroscopy (EIS). For a commercially available graphite/nickel-cobalt-aluminum-oxide lithium-ion cell, the cell impedance increases significantly below SOC20%, while the impedance in the medium SOC region (SOC20%–SOC80%) remains low with only minor changes. This impedance behavior is mostly due to the elementary processes of cathode reactions in the cell. Among the impedance values (Z, Z′, Z″), the imaginary component of Z″ regarding cathode reactions changes heavily as a function of SOC, in particular, when the EIS measurement is performed around 0.1 Hz. Thanks to the significant difference in the time constant of cathode reactions between ≤SOC10% and ≥SOC20%, a single-frequency EIS measurement enlarges the difference in impedance between balanced and unbalanced cells in the module and facilitates an ~80% improvement in the detection signal compared to results with conventional EIS measurements.

Salivary cortisol concentration and its circadian variation were detected by optimizing the ionic concentration of a solution during the immobilization of aptamers on a field-effect transistor bios...

In all-solid-state batteries (ASSB), increasing the thickness of electrodes is essential for increasing the energy density. However, this limits the C-rate performance, particularly for electrodes with a large volume fraction of active materials (AMs), transport of ions in the electrode is hindered, leading to poor utilization of AMs in ASSBs. To accelerate the development of ASSBs, it is highly desirable to develop analytical methods for understanding the utilization of AMs in thick electrodes. In this paper, we propose a novel impedance analysis method using the transmission line model (TLM) for estimating the utilization of AMs in an electrode in terms of effective electrode thickness. In the TLM model, electrode thickness is treated as a variable instead of a fixed parameter in the conventional sequence. Hence, the modified C-rate performance considering the TLM-calculated thickness exhibits an identical trend regardless of the actual electrode thickness, suggesting the calculated electrode thickness reflects the effective electrode thickness. This indicates effective utilization of AMs for electrochemical reactions. We also demonstrate the versatility of this method by using different electrode specifications.

Field effect transistor (FET) biosensors are capable of detecting various biomolecules, although challenges remain in the detection of uncharged molecules. In this study, the detection of uncharged cortisol was demonstrated by interfacial design using a technique to immobilize target-bound aptamers. The target-bound aptamers, which formed a higher-order structure than target-unbound aptamers, expanded the distance between adjacent aptamers and reduced the steric hindrance to the conformational change. The density-controlled aptamers efficiently induced their conformational changes with the cortisol binding, which resulted in the improvement of the sensitivity of FET biosensors.

Lithium-ion capacitors (LICs) are energy storage devices that bridge the gap between electric double-layer capacitors and lithium-ion batteries (LIBs). A typical LIC cell is composed of a capacitor-type positive electrode and a battery-type negative electrode. The most common negative electrode material, graphite, suffers from low rate capability and cyclability due to the sluggish kinetics of the Li+ intercalation/de-intercalation process. In this work, metal chloride-pillared graphite, which has recently attracted attention as high-rate LIB anodes, is applied as the negative electrode for LICs for the first time to overcome this drawback. It is shown that AlCl3-graphite intercalation compounds (AlCl3-GICs) with a wide interlayer spacing benefits faster Li+ diffusion. The low molecular weight and conversion reaction of the AlCl3 pillar further enhances the specific capacity per mass. An optimized LIC cell comprised of a AlCl3-GIC negative electrode and activated carbon as the positive electrode exhibited higher energy and power densities compared to LICs using graphite as the negative electrode, and displayed stable cycling performance with 85% capacity retention after 10,000 charge/discharge cycles. The AlCl3-GICs synthesized in this work displayed improved electrochemical performances and have the potential to replace the graphite electrode in conventional LICs.

Coulombic efficiency (CE) has been widely used in battery research as a quantifiable indicator for the reversibility of batteries. While CE helps to predict the lifespan of a lithium-ion battery, the prediction is not necessarily accurate in a rechargeable lithium metal battery. Here, we discuss the fundamental definition of CE and unravel its true meaning in lithium-ion batteries and a few representative configurations of lithium metal batteries. Through examining the similarities and differences of CE in lithium-ion batteries and lithium metal batteries, we establish a CE measuring protocol with the aim of developing high-energy long-lasting practical lithium metal batteries. The understanding of CE and the CE protocol are broadly applicable in other rechargeable metal batteries including Zn, Mg and Na batteries. Coulombic efficiency (CE) has been frequently used to assess the cyclability of newly developed materials for lithium metal batteries. The authors argue that caution must be exercised during the assessment of CE, and propose a CE testing protocol for the development of lithium metal batteries.

Electrochemical impedance spectroscopy has been widely used to understand the chemistry and physics of battery systems. This review covers electrochemical impedance spectroscopy used for the interpretation of impedance data of lithium-ion batteries (LIBs) from advanced equivalent circuit models to the mathematical model, which is developed by John Newman. In addition, as a method to realize an energy-sustainable society using diagnostics based on the combination of LIBs and electrochemical impedance spectroscopy, on-board diagnostics of battery packs are achieved based on an input signal generated by a power controller in a battery management system instead of the conventionally used frequency response analyzer. The diagnostic system is applicable to energy management systems which are installed in homes, buildings, and communities, accumulating the impedance data on state of health of LIBs. Finally, a future possibility regarding the diagnostics of battery packs coupled with the machine learning of impedance data is introduced.

In lithium–sulfur (Li–S) batteries, the impregnation of sulfur into electrically conductive materials of porous carbon plays a significant role in preventing the dissolution of lithium polysulfide (LiPS) into an electrolyte solution and improving cycling performance. However, this strategy does not render high-energy density to Li–S cells because of the limited amount of sulfur in porous carbon. Once the sulfur overflows out of porous carbon because of the significant volume change occurring during charge–discharge cycling, the LiPS formed outside porous carbon probably diffuses toward the anode, leading to poor cycling performance. In this study, the poly-2-acrylamido-2-methylpropanesulfonic acid (AMPS)-based polymer incorporated into the sulfur/porous carbon composite cathode in a Li–S cell effectively suppresses LiPS dissolution even when sulfur is present outside porous carbon, achieving good cycling performance with a capacity retention of 72% at the 100th cycle. Herein, the polymer used is poly-AMPS with a crosslinker of N-[tris(3-acrylamidopropoxymethyl)methyl]acrylamide, which is synthesized using 2-hydroxy-2-methylpropiophenone as the photoinitiator. The characteristics of the as-synthesized AMPS-based polymer and sulfur–carbon composite cathode are meticulously investigated by scanning electron microscopy–energy-dispersive X-ray spectrometry, transmission electron microscopy, dynamic light-scattering analysis, thermogravimetric analysis, and X-ray diffraction.

Among numerous findings by human beings, electrodeposition is of great importance in the whole invention and is getting to be a core technology to date. The applications of electroplating used in electronics devices, magnetic recording heads and media, chemical biosensors, and batteries are some typical examples surrounding our present world. Looking back on the history of electrodeposition, the first trial was carried out in the Mesopotamian-era in 1500 BC, which was a Sn plating on iron wares. For Japan, the beginning of plating was performed back in the 6th century for a Au amalgam plating on the Buddha statue at Asuka-era Temple. Hence, the technology of electrodeposition has been developed and evolved for a long period of time along with humankind. While electrodeposition is known to be a traditional way to form metal or non-metal ions on various substrates, it is still kept being one of the cutting edge technologies to date. Because desired thin films, such as CoFeNi for hard disk and Cu wiring for silicon devices, can be easily obtained by the fine control of the chemistry on the interface between the electrode and electrolyte. The sequential high-throughput with outstanding cost effectiveness also push forward this technology to practical applications in various industrial fields. An example of the fine control of deposited films popped up in our mind is the idea of UPD (underpotential deposition) by ad-atom in 1978. Such an idea of ppm or ppt content of metal ions in the plating bath resulted in the practical realization of electroless plating disk for PATTY HDD device (1981 NEC,NTT). Electrodeposition is also known to be a game-changer in the scientific history as well. For the fabrication of soft magnetic materials, the electrodeposited thin film of Co65Ni23Ni12 achieved low-Hc with high-Bs for the first time, which was breaking the common sense that high-Bs is incompatible with low-Hc in soft magnetic materials. [1, 2] Such an electroplating technology is on going to the next stage for 3D memories. Ever since electrodeposition was conducted in earnest by Jacobi et al in 1837, its practical use in sub-micron scale was established in 1997 as damascene process to ULSI internal wiring technology and is now available to handle atomic-scale of fabrication in various fields. This year marks the 100th anniversary of the establishment of the ECS Electrodeposition Division. There is no doubt that ECS has contributed significantly to the development of the Electrodeposition field since 1922. In today's lecture, we will introduce our research concept on electrodeposition in the various fields based on electrochemistry, such as magnetism, sensors, and electronics on the basis of our achievements of their practical use for future industrial usage including battery devices. [3] [1] T. Osaka et al., “A soft magnetic CoNiFe film with high saturation magnetic flux density and low coercivity”, Nature, 392, 796 (1998). [2] T. Osaka et al., “Influence of crystalline structure and sulfur inclusion on corrosion properties of electrodeposited CoNiFe soft magnetic films”, Journal of the Electrochemical Society, 146, 2092 (1999). [3] T. Osaka, “Spotlight on Japanese Battery Technologies”, Nature jobs, 2015. Figure 1

In this work, we present a powdered Si-O-C composite, namely pSi-O-C composite, synthesized by electrodeposition harvesting method. This new type of the Si-O-C composite shows impressive results, such as outstanding cyclability with a good discharge capacity of 616 mAh g−1 which reached 10,000 cycles, and a remarkable coulombic efficiency of 99% at the 10,000th cycle. Furthermore, the pSi-O-C composite demonstrates the highest amounts of loaded silicon compared to different types of Si-O-C composite deposited on a Cu and CNTs/Cu substrate.

Here we report an ‘injection’ strategy to introduce transportable Li-ion in the metallic Li free sulfur-graphite (S-G) pouch type full cell, which could alleviate the safety issues from Li dendrites. A novel process with organolithium reagent is used to reduce S to Li2S rapidly during assembling the pouch type full cell. The sublimation property of the side product enables the in-situ injection in the pouch type cell, which will not introduce impurities. In addition, this ‘injection’ strategy avoids the drawbacks from the instability of the Li2S to moisture, which could largely reduce the production cost and improve the practical energy density of the cell. The injected Li2S-G battery shows quite stable cyclability with a capacity of 640 mAh g−1 at 0.1 C rate. This in-situ ‘injection’ method provides an effective and practical way to produce Li metal free sulfur Li-ion battery with alleviated safety issues.

Herein, we synthesized the structural stabilized Si-O-C composite using carbon nanotubes (CNTs). The Si-O-C/CNTs is employed and tested as an anode for lithium-ion batteries (LIBs) assembled with the LiCoO2 cathode. Through the usage of CNTs, it is possible to improve the cyclability and capacity retention ratio by enhanced structural stability. The enhanced electrochemical performance of LiCoO2//Si-O-C full-cell with CNTs indicates the high potential as a way to produce the high-performance LIBs.

We describe a facile and simple solid-state thermolysis route for the preparation of Co, Ni, and Fe phosphide nanoparticles embedded in amorphous carbon using an organometallic complex. This was achieved by using a suitable organometallic complex in a single step synthetic route without using any solvent or catalyst. The advantage of using such precursor was to offer a source for metal, phosphorus and carbon without using any additional sources. The morphology of products was characterized by transmission electron microscopy, scanning electron microscopy and nature of carbon was analyzed using the Raman microscope and X-ray diffraction. The electrocatalytic oxygen evolution reaction (OER) activity and stability of the metal phosphide nanostructure was evaluated using the rotating disk electrode technique. The CoP, NiP and FeP exhibit the OER overpotential of 370, 380 and 550 mV at 10 mA cm−2, respectively in 0.1 M KOH electrolyte. Among prepared phosphide catalysts, cobalt phosphide shows a lowest Tafel slope indicate favorable kinetics for the OER activity than nickel and iron phosphide catalysts.

Lithium-ion batteries are required to have high-power density, that is to reduce impedance, for use in electric vehicles. This paper focuses on interfacial resistance between the cathode layer (CL) and the current collector (CC) observed at high frequencies, which is generally attributed to a resistance of surface film like SEI. To investigate the interfacial resistance systematically, different interfaces between the CL and the CC were prepared by controlling the press rate for the cathode preparation, or by introducing a carbon under-coating layer (CUL), followed by electrochemical impedance spectroscopy (EIS). The interfacial resistance between the CL and the CC prepared with an insufficient press rate or without a CUL was extremely high for the entire cathode. From the cathode cross-sectional observation, it was observed that this high interfacial resistance was caused by low contact rate at the interface. Using a pouch-type symmetric cell, EIS revealed that the interfacial resistance is attributed to electric resistance, that is, contact resistance at the interface. Also, the other resistances were attributed to be the ionic resistance of the electrolyte and pores in the cathode, and the charge transfer resistance of the cathode. Furthermore, the effectiveness of the CUL was shown to decrease the cathode impedance.

Lithium-ion capacitors (LICs) operate by two mechanisms, namely a double-layer mechanism based on a capacitor-like positive electrode and the intercalation mechanism of a battery-like negative electrode. Hence, well-designed reaction kinetics between the positive electrode and negative electrode are essential for optimizing LIC full-cell configurations. In this study, we investigated the influences of fluoroethylene carbonate (FEC) or vinylene carbonate (VC) as electrolyte additives on full-cell performance of LICs. We confirmed that the internal resistance of graphite increased with the use of FEC, which degraded the cyclability of the LIC full-cell. Conversely, LICs consisting of the VC additive had good cyclability over 4000 cycles owing to the solid electrolyte interphase (SEI) containing polymeric species. This detailed investigation into the function of SEI compounds derived from VC additives and their effect on cyclability will provide new insights into optimization of LIC full-cell configurations with appropriate electrolyte additives.

Both the high sulfur loading cathode and less electrolyte are the most important parameters to realize lithium-sulfur batteries with high energy density. A high sulfur loading cathode was achieved by using 3D structured aluminum foam to act as a support structure and current collector. Moreover, the energy density close to 200 Wh kg−1 was successfully obtained by decreasing the electrolyte in the pouch cell. 5 Ah cell was developed by using the six sheets of the cathode in the cell. Recently, a multi-layer pouch-type cell with a high capacity of 5 Ah and a high energy density of 300 Wh kg−1 was successfully developed with technically reoptimized preparation conditions. These results indicate the possibility of the development of a lithium-sulfur battery with discharge capacity and high energy density for commercial use.

In order to establish the universality of the excess heat production in electrochemical reaction, under a high magnetic field, as one of the most fundamental electrochemical reactions, the case of ferricyanide-ferrocyanide redox reaction was examined, where ionic vacancies with ± 1 unit charge were collided by means of magnetohydrodynamic (MHD) flow. As a result, from the pair annihilation of the vacancies with opposite signs, beyond 7 T, excess heat production up to 25 kJ·mol−1 in average at 15 T was observed, which was attributed to the liberation of the solvation energy stored in a pair of the vacancy cores with a 0.32 nm radius, i.e., 112 kJ·mol−1. Difference between the observed and expected energies comes from the small collision efficiency of 0.22 due to small radius of the vacancy core. Ionic vacancy initially created as a by-product of electrode reaction is unstable in solution phase, stabilized by releasing solvation energy. Ionic vacancy utilizes the energy to enlarge the core and stores the energy in it. As a result, solvated ionic vacancy consists of a polarized free space of the enlarged core surrounded by oppositely charged ionic cloud. The accuracy and precision of the measured values were ascertained by in situ standard additive method.

The controlled design of biosensors based on the photo-electrochemical technique with high selectivity, sensitivity, and rapid response for monitoring of mono-bioactive molecules, particularly dopamine (DA) levels in neuronal cells is highly necessary for clinical diagnosis. Hierarchical carbon-, nitrogen-doped (CN) nickel oxide spear thistle (ST) flowers associated in single-heads (S), and symmetric and asymmetric-double heads (D and A, respectively) that are tightly connected through a micrometric dipole-like rod or trunk were fabricated by using a simple synthetic protocol. The CN-ST flower heads were decorated with dense nano-tubular like hedgehog needle skins in vertical alignments. These designated architectures are key features for creating biosensor surface electrodes for photo-electrochemical, ultrasensitive screening of mono-bioactive molecules. The exceptional electrode designs produced numerous catalytically active sites, large surface area, and high electron-transfer mobility. The active coating of carbon–nitrogen nanospheres significantly enhanced the photo-electrocatalytic activity of the prepared biosensor electrodes and prevented leakage of photocatalytic activity under long-term exposure to irradiation. Among all photo-electrochemical assays, the biosensors showed significant sensitivity and selectivity for DA in the presence of interfering molecules such as ascorbic acid (AA), uric acid (UA), adrenaline (A), and noradrenaline (NA). The photo-electrochemical property of the CN-SST-{110} crystal surface electrode showed significant sensing performance for DA in terms of unimpeded diffusion pathways, a wide concentration-detection range, and a low detection limit, even in the presence of potentially interfering molecules compared with other electrode-modified CN-DST-{111} and CN-AST-{101} crystal surfaces. Furthermore, the CN-SST photo-biosensor electrode shows potential in the selective and sensitive determination of DA in real samples, such as human serum and secreted DA from living cells. This finding indicates that the hierarchical ST biosensor may enable analytical discrimination and monitoring of DA and can be employed for clinical diagnosis application.

The dissolution of lithium polysulfide (Li2Sx, 4 ≤ x ≤ 8, LiPS) during charge/discharge testing is a critical issue hindering the practical application of lithium-sulfur batteries (LSBs). To suppress LiPS dissolution, we propose a facile method to fabricate a Li-ion-conductive polymer layer by photopolymerization. The electrochemical performance of LSBs was investigated by preparing small pouch cells containing a three-dimensional (3D) structured sulfur-based cathode that either was or was not layered with the new polymer. Analysis of the electrolyte in the LSB pouch cell by UV-Vis spectroscopy revealed that a 3D S cathode with polymer layer shows a good discharge capacity of 535 mA h g−1 and a coulombic efficiency (CE) of over 96% after 40 cycles. In comparison, the 3D S cathode without a polymer layer has a poor discharge capacity of 389 mA h g−1 and a CE of over 22% after 40 cycles. The dissolution suppressing ability of our new polymer layer demonstrates promise for the practical application of LSBs.

Cycle life of series-connected lithium-ion battery (LIB) modules in the presence or absence of an overcharged cell is reported, and degradation behavior is characterized by electrochemical impedance spectroscopy (EIS) and differential voltage analysis (DVA). Three-stage capacity decay is solely observed in modules in the presence of an overcharged cell, which is exposed to a state of charge (SoC) of ≥105% during cycling. The module without overcharged cells or with an overcharged cell at an SoC of

A system using a high-speed and high-precision X-ray inspection system for testing internal short circuits in lithium-ion batteries (LIBs) was firstly developed for the safety test on LIBs. X-ray transmission moving images of the anode and cathode were obtained in the layered LIB structure. The nail-penetration test was chosen to test for the presence of an internal short circuit. This system would allow direct observation of smoke generation inside outside the battery, ballooning of the pouch, as well as changing layered structures of electrodes in real time. Since the results of a conventional nail-penetration test are indicated only by smoke generation, fire, or explosion, this new system allows electrode changes in the pouch to be observed for the first time. This system is expected to lead to great developments in the safety of LIBs.

Sulfur (S) Li-ion battery which use the metallic Li free anode is deemed as a promising solution to conquer the hazards originating from Li metal. However, stable cycling performance and low production price of the S Li-ion battery still remain challenging. Here, we propose a S-LixC full cell system by paring a S cathode and a pre-lithiated graphite anode which is cheap and commercially available. It shows stable cycling performance with a capacity around 1300 mAh (g-S)−1 at 0.2 C-rate and 1000 mAh (g-S)−1 at 0.5 C-rate. In addition, 0.1% per cycle capacity fading rate with a capacity retention of 880 mAh (g-S)−1 after 400 cycles at 0.2 C-rate has been achieved. The pre-formed solid electrolyte interphase (SEI) layer on the pre-lithaited graphite anode largely contributes to the high capacity performance. Notably, a 10-times-enlarged scale of S-LixC laminate type full cell has been assembled with high capacity performance (around 1000 mAh (g-S)−1) even after high rate cycling.

As amyloid-β peptide 1–42 (Aβ42) was found to be an emerging and important biomarker for Alzheimer's disease, the detection of this peptide in biological samples such as human serum (HS) has become very important for evaluating the potential disease state and determining the appropriate treatment. In this study, we developed an electrical analysis strategy based on a field effect transistor (FET) biosensor as a simple and reliable technique for confirming the presence of Aβ42 aggregates (fibrils) in biological samples. By utilizing Congo red immobilized on the FET gate surface as a biorecognition element, we observed remarkable sensitivity and specificity for detecting Aβ42 fibrils. Furthermore, we optimized the procedure to minimize the interference of abundant human serum albumin for the detection system using HS samples. The optimized system of Congo red-immobilized FET enables measurement of Aβ42 fibrils in the 100-pM level in HS samples, which is lower than its clinical concentration. The FET device can be applied as a biosensing system for mass and routine screening of peptide biomarkers related to Alzheimer's disease. Keywords: Field effect transistor biosensor, Amyloid beta fibrils, Alzheimer's disease, Human serum albumin, Albumin-amyloid beta complexes

A solvate ionic liquid (SIL) of highly concentrated 4.0 M lithium nitrate (LiNO3) in a dimethylsulfoxide solution is introduced for lithium-oxygen batteries. As a redox mediator (RM), highly concentrated LiNO3 in the SIL works more effectively than the lower concentrated one to decompose lithium peroxide (Li2O2) on the cathode with an extremely low charging voltage of 3.6 V. In addition, X-ray photoelectron spectroscopy analysis confirms that side products during discharging and charging are markedly restricted in the SIL. The low solubility of Li2O2 intermediate (LiO2) in the SIL may be an important reason for the restriction of side products.

An anionic polymer coating produced by ultraviolet curing and thermosetting to suppress polysulfide dissolution of the sulfur cathode for lithium-sulfur batteries was investigated. An sulfur/Ketjenblack cathode with a high sulfur loading of 10 mg cm−2 was prepared using a three-dimensional foam current collector. From the current rate and cycle characteristics, the cross-linked polymer coating suppressed the polysulfide dissolution, and the discharge capacities were 1031 and 414 mAh g−1-sulfur at 0.1 and 1.0C, respectively. In a long-term cycle test of 300 cycles, a capacity retention rate was 41%. An average coulombic efficiency was 91% throughout the cycles.

Addressing the reuse of lithium ion batteries (LIBs) extracted from used battery packs is an option for addressing environmental concerns. To guarantee their safety, the development of non-destructive analysis to identify LIBs exposed to over-discharge is mandatory. In this study, over-discharge-induced degradation in graphite/nickel cobalt aluminum oxide (NCA) lithium ion cells was investigated using differential voltage analysis (DVA) and electrochemical impedance spectroscopy (EIS). Two-stage cell capacity decay was solely observed in the deep over-discharge cycling at a lower cutoff voltage (LCV) of 1.00 V; in the first stage, the capacity gradually decreased similar to that at LCV ≥ 2.50 V, and then decreased steeply. In the over-discharge cycling, the DVA results confirmed that the electrode balancing between the anode and cathode contribute to increasing the cell capacity, whereas the cathode capacity decreased as cycling progressed, suggesting that electrode degradation induced by over-discharge is difficult to assess using the cell capacities. EIS analysis revealed that the charge-transfer resistance and interfacial capacitance of the NCA cathode changed markedly in the first stage under over-discharge. This study reports a meticulous characterization of over-discharge of LIBs using non-destructive electrochemical analysis and introduces a critical aspect for their detection before serious cell deterioration.