This study introduces a novel method for integrating aluminum flexible printed circuit boards (FPCBs) and copper FPCBs into battery management systems (BMS) using and instantaneous large area facial ...laser source soldering. Achieving a robust bonding strength of 65 MPa involved applying 600 W of laser power for 2 s, enhancing atom diffusion and promoting intermetallic compound (IMC) growth. Finite Element Method (FEM) simulations revealed variations in heat transfer between Al and Cu, affecting IMC thickness at interfaces. Formation of the (Cu, Ni)3Sn4 phase within solder, and variations in laser output significantly influenced solder joint orientation and Al electrode nucleation. Excessive laser power (>800 W) caused critical damage, such as delamination at the Al-PI interface, altering fracture modes and bonding strength. Furthermore, with a detailed examination of the laser soldering phenomenon through both experimental and numerical investigations, this study provides a thorough understanding of the different soldering mechanisms in conventional reflow soldering compared to instantaneous uniform large-area heat source laser soldering. These insights provide new design and material considerations to replace the conventional wiring harness with Al/Cu FPCB lap joints which optimize the circuitry and reducing BMS volume.
Exploring bifunctional electrocatalysts to lower the activation energy barriers for sluggish electrochemical reactions for both the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) ...are of great importance in achieving lower energy consumption and higher conversion efficiency for future energy conversion and storage system. Despite the excellent performance of precious metal-based electrocatalysts for OER and ORR, their high cost and scarcity hamper their large-scale industrial application. As alternatives to precious metal-based electrocatalysts, the development of earth-abundant and efficient catalysts with excellent electrocatalytic performance in both the OER and the ORR is urgently required. Herein, we report a core–shell CoFeS2@CoS2 heterostructure entangled with carbon nanotubes as an efficient bifunctional electrocatalyst for both the OER and the ORR. The CoFeS2@CoS2 nanocubes entangled with carbon nanotubes show superior electrochemical performance for both the OER and the ORR: a potential of 1.5 V (vs. RHE) at a current density of 10 mA cm−2 for the OER in alkaline medium and an onset potential of 0.976 V for the ORR. This work suggests a processing methodology for the development of the core–shell heterostructures with enhanced bifunctional performance for both the OER and the ORR.
High-performance oxygen evolution reaction (OER) electrocatalysts are needed to produce hydrogen for energy generation through a carbon-free route. In this work, the solution combustion synthesis ...(SCS) method was employed to synthesize mixed phases of Co- and Mn-based oxides, and the relationships between the crystalline structure and the catalytic properties in the mixed phases were established. The mixed phases of Co- and Mn-based oxides shows promising OER properties, such as acceptable overpotential (450 mV for 10 mA∙cm−2) and Tafel slope (35.8 mV∙dec−1), highlighting the use of the mixed phases of Co- and Mn-based oxides as a new efficient catalysts for water splitting. Electronic structure of the mixed phases of Co- and Mn based oxides is studied in detail to give insight for the origin of high catalytic activities. In addition, excellent long-term stability for OER in alkaline media is achieved for the mixed phase of Co- and Mn based oxides.
The development of electrochemical devices for renewable energy depends to a large extent on fundamental improvements in catalysts for oxygen evolution reactions (OERs). OER activity of transition ...metal sulfides (TMSs) can be improved by compositing with highly conductive supports possessing a high surface-to-volume ratio, such as reduced graphene oxide (rGO). Herein we report on the relationship between synthetic conditions and the OER catalytic properties of TMSs and rGO (TMS–rGO) hybrids. Starting materials, reaction temperature and reaction time were controlled to synergistically boost the OER catalytic activity of TMS–rGO hybrids. Our results showed that (i) compared with sulfides, hydroxides are favourable as starting materials to produce the desired TMS–rGO hybrid nanostructure and (ii) high reaction temperatures and longer reaction times can increase physico-chemical interaction between TMSs and rGO supports, resulting in highly efficient OER catalytic activity.
In this work, we prepared spinel-type NiCo
O
(NCO) nanopowders as a low-cost and sensitive electrochemical sensor for nonenzymatic glucose detection. A facile and simple chemical bath method to ...synthesize the NCO nanopowders is demonstrated. The effect of pH and annealing temperature on the formation mechanism of NCO nanoparticles was systematically investigated. Our studies show that different pHs of the precursor solution during synthesis result in different intermediate phases and relating chemical reactions for the formation of NCO nanoparticles. Different morphologies of the NCO depending on pHs are also discussed based on the mechanism of growth. Electrochemical performance of the prepared NCO was characterized towards glucose, which reveals that sensitivity and selectivity of the NCO are significantly related with the final microstructure combined with constituent species with multiple oxidation states in the spinel structure.
We reveal the mechanism of the cold silver sinter joining process using time-dependent characteristics of Ag–Au interactions grown in the highly (111) orientation. In the initial (∼15 min) state at ...175 °C, the Ag–Au inter-diffusion layers developed strongly in the (001) direction, and with increasing time (∼60 min), they switched epitaxial growth in the (111) orientation. The die-bonding strength was significantly improved from 14.9 MPa to 37.8 MPa when the sintering time increased from 15 min to 60 min. The gradual Ag–Au epitaxial growth behavior with a higher stacking-fault energy (SFE) at 175 °C was the dominant factor linearly increasing the cold silver sinter joining strength and ultimately maximizing energy absorption leading to fracture. The surface finish of Au, which can contribute to the time-dependent growth of Ag–Au inter-diffusion layers, underwent a dramatic transformation from a Cube texture to a γ-fiber texture over time. This change was attributed to the micro/nanoscale shear deformation, and reduction of the twin boundary fraction. This study unveiled the in-depth fundamental mechanism for strengthening and pressureless cold sinter joining of Ag–Au epitaxial layers by comprehensively considering this texture behavior, changes in X-ray residual stress, and mechanical properties.
Achieving carbon neutrality is important to solve environmental problems and thus requires decarbonizing manufacturing processes to reduce greenhouse gas emissions. The firing of ceramics, including ...calcination and sintering, is a typical fossil fuels-driven manufacturing process that requires large power consumption. Although the firing process in manufacturing ceramics cannot be eliminated, an effective firing strategy to reduce processing steps can be a choice to lower power consumption. Herein, we suggest a one-step solid solution reaction (SSR) route to manufacture (Ni, Co, and Mn)O
(NMC) electroceramics for their application in temperature sensors with negative temperature coefficient (NTC). Additionally, the effect of the one-step SSR route on the electrical properties of the NMC is investigated. Similar to the NMC prepared using the two-step SSR route, spinel structures with dense microstructure are observed in the NMC prepared via the one-step SSR route. Based on the experimental results, the one-step SSR route can be considered as one of the effective processing techniques with less power consumption to manufacture electroceramics.
Recently, aqueous Zn ion rechargeable batteries have drawn increasing research attention as an alternative energy storage system relative to the current Li ion batteries due to their intrinsic ...properties of high safety, low cost, and high theoretical volumetric capacity. Nevertheless, unwanted dendrite growth on the Zn anode and unstable cathode materials restrict their practical application. In this study, a unique 2D MoS2 coating on Zn anode using an electrochemical deposition method has been developed for preventing dendrite growth and intricate side reactions. The coated MoS2 layer is a vertically-oriented structure, makes easy flow of Zn ions and uniform electric field distribution on the anode, resulting in uniform stripping and plating of Zn2+. In addition, the MoS2 coating enhances the anodic diffusion of Zn ions and reduces the series resistance as confirmed by the EIS analysis, therefore, improves the overall battery performance. The full cell assembled with the MoS2-Zn anode and MnO2 cathode exhibits an excellent reversible specific capacity of 638 mAh/g at 0.1 A/g and stable cycle performance over 2000 cycles with no dendrite formation at the Zn electrode. The presented MoS2 coating on Zn is a facile, scalable and promising technology for practical Zn ion batteries with a long life cycle and high safety.
Rechargeable aqueous Zn ion batteries (AZIBs) have attracted significant attention as a promising alternative to Li‐ion batteries due to the use of water‐based electrolytes, high energy density per ...volume, and cost‐effectiveness. However, various parasitic reactions relating to hydrogen evolution reaction, corrosion, and dendrite growth in the Zn anode can result in the degradation of the electrochemical performance of AZIBs. Therefore, understanding the mechanisms underlying these various phenomena and their role in the electrochemical performance of AZIBs provides valuable insights for the development of anode and cathode materials. In this study, we investigate the effect of the MnO2 cathode and Al2O3‐coated Zn anode on the electrochemical performance of the AZIBs. The experimental results show that Al2O3‐coated Zn anodes efficiently suppress the dendrite growth on the Zn. However, significant cycling fade of the full cell comprising of an Al2O3‐coated Zn anode and MnO2 cathode was observed during continuous charge/discharge cycles. The poor cycle performance can be mainly attributed to the phase transformation of MnO2–Mn2O3 and the formation of various byproducts, which highlights the importance of the electrochemical stability of cathode materials in AZIBs to improve the cycle performance.
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