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Recent progress in battery recycling is critically reviewed, including closed-loop design of new batteries and recycling-oriented design of battery configurations and components, together with an appraisal of predicted future research.

To better understand the formation and evolution processes of soot, the two-color laser induced incandescence diagnostic method was applied on a single cylinder optical direct injection spark ignition engine. Soot volume fraction was measured, and soot distribution was imaged as cyclic fuel quantity changes. The results show that 45.5 mg/cycle generates the most soot at the same measure plane. Pool fire dominates the formation of soot in the tested engine and generates more soot on the top surface of the piston near the injector. In-cylinder soot increases until 42°CA ATDC and then reduces due to oxidation. Pool fire continues through the expansion stroke till 52°CA ATDC, and then soot cloud gathers near the 10 mm plane. After 82°CA ATDC, in-cylinder soot basically in equilibrium, and residual soot moves follow the in-cylinder flow randomly and evenly distributes within the whole combustion chamber. With increasing cyclic fuel quantity, particles number concentration gradually increases and their distribution present dual-peak shape. In detail, 45.5 mg/cycle emits the most accumulation mode particles while 52 mg/cycle emits the most nucleation mode particles.

We present mesoporous bismuth nanosheets as a model to study the charge-storage mechanism of Mg/Bi systems in magnesium-ion batteries (MIBs). Using a systematic spectroscopy investigation of combined synchrotron-based operando X-ray diffraction, near-edge X-ray absorption fine structure and Raman, we demonstrate a reversible two-step alloying reaction mechanism Bi↔MgBi↔Mg3 Bi2 . Ab-initio simulation methods disclose the formation of a MgBi intermediate and confirm its high electronic conductivity. This intermediate serves as a buffer for the significant volume expansion (204 %) and acts to regulate Mg storage kinetics. The mesoporous bismuth nanosheets, as an ideal material for the investigation of the Mg charge-storage mechanism, effectively alleviate volume expansion and enable significant electrochemical performance in a lithium-free electrolyte. These findings will benefit mechanistic understandings and advance material designs for MIBs.

As a typical layered electrode material, sodium titanate has shown high energy density but poor ion transportation kinetics for sodium-ion batteries. Hence, optimizing the migration of larger ions in such a layered structured material is of great significance for sodium-ion batteries. Herein, we rationally construct dual-shell structured titanates with hydrogenated-induced oxygen vacancies to regulate the tunnels for Na ion transport structurally and atomically. Serving as anodes for batteries, the as-prepared samples exhibit enhanced rate performance compared to the one without oxygen vacancies. The result demonstrates an effective approach to optimize ion transport kinetics.

Summary Nanostructured alloy anodes have been successfully used in several kinds of rocking-chair batteries. However, a full picture of the origin of their improved reversible capacity remains elusive. Here, we combine operando synchrotron-based X-ray powder diffraction and ex situ X-ray absorption near-edge structure spectroscopy to study the double-shell structured bismuth boxes as anodes in potassium-ion batteries to reveal the origin of their improved capacity. The nanostructured bismuth anode offers an enhanced capability to tolerate the volume expansion under a low current density of 0.2 C, resulting in a more complete alloy reaction. Additionally, under a high current density of 2 C, nanostructured bismuth anode with larger surface area offers more sites to electrochemically alloy with potassium and results in a lower average oxidation state of bismuth. These findings offer guidance for the rational design and engineering of electrode materials according to the current density for rocking-chair batteries.

Commercial diesel vehicles that comply the China/EURO VI emission regulations are generally equipped with selective catalytic reduction (SCR) systems for reducing [Formula: see text] emission and [Formula: see text] sensors at its downstream for accurate closed-loop control. However, [Formula: see text] sensors have significant ammonia cross-sensitivity pushing up their readings. Moreover, for the closed-loop control of SCR systems effectively estimating the critical states from the [Formula: see text] sensor readings remains a further challenge. In this paper, an ammonia cross-sensitivity model with segmented sin and quadratic composite functions describing high frequency characteristics is established by analyzing the experimental data of an SCR system. A control-oriented three-states model of an SCR system is established, and based on it an extended Kalman filter (EKF) observer coupled to the ammonia cross-sensitivity model is proposed. The simulation results show that from the [Formula: see text] sensor readings the EKF observer can effectively estimate the deterioration trend of the [Formula: see text] and [Formula: see text] emissions, and describe the dynamic change process of the ammonia coverage rate. The experimental results under the four non-excitation cycles show that the EKF observer can effectively estimate the deterioration trend, that the average estimated accuracy of [Formula: see text] and [Formula: see text] during their deterioration stage can respectively reach 86.16% and 54.87%, and that the observer has better robustness to disturbances from the operating conditions.

To simultaneously achieve high fuel efficiency and low emissions in a diesel hybrid electric vehicle (DHEV), it is necessary to optimize not only power split but also exhaust thermal management for emission aftertreatment systems. However, how to coordinate the power split and the exhaust thermal management to balance fuel economy improvement and emissions reduction remains a formidable challenge. In this paper, a hierarchical model predictive control (MPC) framework is proposed to coordinate the power split and the exhaust thermal management. The method consists of two parts: a fuel and thermal optimized controller (FTOC) combining the rule-based and the optimization-based methods for power split simultaneously considering fuel consumption and exhaust temperature, and a fuel post-injection thermal controller (FPTC) for exhaust thermal management with a separate fuel injection system added to the exhaust pipe. Additionally, preview information about the road grade is introduced to improve the power split by a fuel and thermal on slope forecast optimized controller (FTSFOC). Simulation results show that the hierarchical method (FTOC + FPTC) can reach the optimal exhaust temperature nearly 40 s earlier, and its total fuel consumption is also reduced by 8.9%, as compared to the sequential method under a world light test cycle (WLTC) driving cycle. Moreover, the total fuel consumption of the FTSFOC is reduced by 5.2%, as compared to the fuel and thermal on sensor-information optimized controller (FTSOC) working with real-time road grade information.

Aqueous Zn-ion batteries (ZIBs) are regarded as alternatives to Li-ion batteries benefiting from both improved safety and environmental impact. The widespread application of ZIBs, however, is compromised by the lack of high-performance cathodes. Currently, only the intercalation mechanism is widely reported in aqueous ZIBs, which significantly limits cathode options. Beyond Zn-ion intercalation, we comprehensively study the conversion mechanism for Zn2+ storage and its diffusion pathway in a CuI cathode, indicating that CuI occurs a direct conversion reaction without Zn2+ intercalation due to the high energy barrier for Zn2+ intercalation and migration. Importantly, this direct conversion reaction mechanism can be readily generalized to other high-capacity cathodes, such as Cu2 S (336.7 mA h g-1 ) and Cu2 O (374.5 mA h g-1 ), indicating its practical universality. Our work enriches the Zn-ion storage mechanism and significantly broadens the cathode horizons towards next-generation ZIBs.

Although Na2Ti3O7-based anodes have been widely investigated in sodium-ion batteries (SIBs), their Na+ storage properties especially high-rate capability and long-term cycling durability are far fr...

Low energy density is the key issue that needs to be addressed for sodium ion batteries. Antimony sulfide (Sb2S3) with high theoretical capacity is considered as an ideal anode, but it suffers from poor electrochemical activity and consequently, low energy density. Simple hollow Sb2S3 structures with high electrochemical activity offer high gravimetric energy density, while large internal voids significantly decrease the volumetric energy density. Here, multi-shell Sb2S3 was synthesized as an anode for sodium ion batteries, exhibiting much higher reversible capacity and gravimetric energy density than the pristine Sb2S3. Moreover, the multi-shell structure presents higher volumetric energy density with enhanced durability than its single-shell counterpart due to the optimized utilization of the inner void. Operando synchrotron-based X-ray powder diffraction (XRPD) was used to verify the enhanced electrochemical activity originated from more complete conversion electrochemical reactions. The multi-shell Sb2S3 design may provide a guide for the development of high-performance hollow structured anodes with preserved high energy density.

The engine starting process presents high particulate emissions in exhaust. This study gives a systematic investigation on particulate emission characteristics, including particulate matter (PM) mass, soluble organic fraction (SOF) mass, C10-C26 n-Alkanes and particle-bound polycyclic aromatic hydrocarbons (PAHs), that have been emitted from a gasoline direct injection (GDI) engine measured by Gas chromatography-mass spectrometry during starting period. The results show that particulate emissions under the warm coolant start condition decline dramatically compared with the cold start condition. 90 % of particulate number (PN) emitted during the cold and warm start periods generally are nucleation-mode particles. Over 50 % PM mass and PAHs emissions are emitted in the first 0–13 s stage. SOF mass accounts more than 60 % in PM mass emissions, especially under the warm coolant start condition. Some C23–C26 n-Alkanes are detected under the cold start condition which demonstrates that partial particulate composition directly comes from lubricant. The concentration of the two ring PAHs is the lowest among PAHs while the four to six ring PAHs are higher under the cold start operation. The toxicity of PAHs which is evaluated by Benzo(a)pyrene equivalent toxicity (BEQ) value of the total PAHs emissions shows a decline of 66.83 % under the warm start condition.

Studies show that the valve lift (VL) of the cam-driven hydraulic variable valve actuation (VVA) can be continuously adjusted in the range of 0&ndash, 8.2 mm by controlling the opening of the throttling valve. In the present study, an orthogonal experiment with interaction was designed to analyze the effect of multi-factor coupling on the VL, valve-seating velocity (VSV), and pressure fluctuation in the valve piston cavity. In order to reduce the pressure fluctuation, the Taguchi method was applied to find the optimal combination of the key parameters including the diameter of the piston, the spring preload of the valve-seating buffer mechanism (VSBM), the spring preload of the valve, and the valve piston mass. The correctness of the VVA simulation model is verified through experiments. Moreover, the pressure fluctuation is analyzed through a numerical simulation. The obtained results showed that as long as the VSV is less than 0.5 m&middot, s-1, the pressure fluctuations in hydraulic VVA can be reduced by several means, such as increasing the spring stiffness of the VSBM and valve, increasing the valve piston area and diameter size of the thin-walled hole, and reducing the valve piston mass and total hydraulic oil volume.

Aqueous batteries are a reliable alternative for next-generation safe, low-cost, and scalable energy storage., Safety concerns about organic media-based batteries are the key public arguments against their widespread usage. Aqueous batteries (ABs), based on water which is environmentally benign, provide a promising alternative for safe, cost-effective, and scalable energy storage, with high power density and tolerance against mishandling. Research interests and achievements in ABs have surged globally in the past 5 years. However, their large-scale application is plagued by the limited output voltage and inadequate energy density. We present the challenges in AB fundamental research, focusing on the design of advanced materials and practical applications of whole devices. Potential interactions of the challenges in different AB systems are established. A critical appraisal of recent advances in ABs is presented for addressing the key issues, with special emphasis on the connection between advanced materials and emerging electrochemistry. Last, we provide a roadmap starting with material design and ending with the commercialization of next-generation reliable ABs.

Research interest and achievements in zinc aqueous batteries, such as alkaline Zn//Mn, Zn//Ni/Co, Zn-air batteries, and near-neutral Zn-ion and hybrid ion batteries, have surged throughout the world due to their features of low-cost and high-safety. However, practical application of Zn-based secondary batteries is plagued by restrictive energy and power densities in which an inadequate output plateau voltage and sluggish kinetics are mutually accountable. Here, a novel paradigm high-rate and high-voltage Zn-Mn hybrid aqueous battery (HAB) is constructed with an expanded electrochemical stability window over 3.4 V that is affordable. As a proof of concept, catalyzed MnO

Soot volume fraction distribution of ethanol blended fuels (ethanol volume fraction 0%, 20%, 40% and 60%, named as E0, E20, E40 and E60) were measured in an optical direct injection spark ignition (DISI) engine by combined laser induced incandescence (LII) and two-color (2C) method. Exhaust particulate matter (PM) emissions were measured by a Combustion DMS500 Fast Particulate Analyzer. For DISI engines, pool fire and the resulting diffusion flame are the main sources of soot in the cylinder. Choosing a suitable measurement plane and detection time, laser induced incandescent can be used to quantitatively measure the soot concentration produced by the pool fire. This research explores the effect of ethanol blending on engine particulate matter by comprehensively analyzing the soot process in the cylinder and exhaust particulate emissions. According to the two-dimensional quantitative soot volume fraction results, the maximum average soot volume fraction of the same fuel on the 10 mm plane is greater than the 5 mm plane; on the same plane, E20 shows the highest soot concentration compared to the other fuel blends which could be the physical properties of the ethanol become apparent. For exhaust particle emissions, ethanol can significantly reduce the total particle number and accumulation mode particle number. E0, E40 and E60 show fairly similar behavior between the exhaust particle emissions and the soot-LII imaging measurements. For E20, however, this is in poor agreement when comparing the soot-LII imaging results to the results of exhaust particle emission measurements.

The effects of coolant’s temperature on emissions of particulate matters (PM) and particle-bound polycyclic aromatic hydrocarbons (PAHs) from a gasoline direct injection (GDI) engine were studied during the start process using gasoline (M0) and gasoline mixed with methanol in 15 % volume (M15). The engine worked at a certain idle speed automatically under different coolant’s temperature conditions after successful start. The experimental data was recorded from 0 to 40 seconds during the start. Results indicated that, there are significant differences in PM and particle-bound PAHs emissions between cold and warm start conditions. Particulate size distribution was measured with the Engine Exhaust Particle Sizer (EEPS) 3090. Compared with M0 fuel, the PM emission of M15 fuel decreased significantly, especially nucleation-mode particulate emission. The mass emission of PM was measured using the Gravimetric method. A same variation trend in PM mass emissions can be inferred for both fuels, i.e. it decreases while the coolant’s temperature increases. Compared with M0 fuel, the PM mass with M15 fuel reduces by 80 % at 20 oC coolant’s temperature. Agilent 7000B GC-QQQ was used to provide both qualitative and quantitative analysis on PAHs. The application of M15 fuel reduces the concentrations of most PAH species compared with M0 fuel, except those with smaller aromatic rings. In addition, Benzo(a)pyrene equivalent toxicity (BEQ) is calculated to evaluate the toxicity of PAHs emissions. The toxicity decreases when the GDI engine starts with higher coolant’s temperature or with M15 fuel.

Confined transformation of assembled two-dimensional MXene (titanium carbide) and reduced graphene oxide (rGO) nanosheets was employed to prepare the free-standing films of the integrated ultrathin sodium titanate (NTO)/potassium titanate (KTO) nanosheets sandwiched between graphene layers. The ultrathin Ti-based nanosheets reduce the diffusion distance while rGO layers enhance conductivity. Incorporation of graphene into the titanate films produced efficient binder-free anodes for ion storage. The resulting flexible NTO/rGO and KTO/rGO electrodes exhibited excellent rate performances and long cycling stability characterized by reversible capacities of 72 mA h g-1 at 5 A g-1 after 10000 cycles and 75 mA h g-1 after 700 cycles at 2 A g-1 for sodium and potassium ion batteries, respectively. These results demonstrate the superiority of the unique sandwich-type electrodes.

Despite the thermal efficiency improvement, gasoline direct injection (GDI) engines are facing with the problem of particulate matter (PM) emissions. In this study, the effects of control parameters (spark advance, injection pressure, excess air ratio and EGR) on the combustion, performance and particulate matter emissions of a GDI engine were investigated. Furthermore, Taguchi method was carried out to determine the optimal combination of factors for the specific best engine output by adopting orthogonal array experiment, and ANOVA analysis was applied to examine the influence levels of tested parameters. Experimental results showed that retarding ignition timing, rising injection pressure, adding proper amount of air and EGR diluents will all reduce particulate number (PN) concentration, and the later three methods will improve fuel economy either. Retarding ignition timing and EGR dilution will increase the fraction of nucleation mode particles, while the other two will reduce it. The optimal combination for the lowest PN is 17° spark timing, 7.0 MPa injection pressure, 60°CA ATDC injection timing and 20% cooled EGR at stoichiometric mode, and 17° spark timing, 7.0 MPa injection pressure, 90°CA ATDC injection timing and 20% cooled EGR at lean-burn mode. The most significant factor that affects NOX emissions and BSFC is EGR mode. Injection timing presents the highest contribution level to PN emissions, especially at lean-burn condition.

A detailed investigation of the impact of injection timing and injection pressure on combustion and particles of a spray-guided GDI engine was conducted, under different engine operating conditions. The results indicated that, more proportion of large particles were emitted when increasing engine load, and the peak of accumulation mode particles moved toward smaller size when rising engine speed. With retarding the injection timing, the in-cylinder pressure and heat release rate rose first and then dropped at 2000 rpm, but they continuously rose at lower or higher speed conditions. The total particles concentration curves at all cases showed a trend of U-shape, and the corresponding timing of the lowest particles concentration advanced as the engine speed or load increased. The minimum value of emitted particles first rose and then fell when increasing load at 2000 rpm conditions, and it continuously rose when increasing speed at 40 Nm conditions. Generally, injection pressure did no sensitively affect combustion process except that it showed a relatively strong impact at low load conditions. However, particulate matter could be effectively inhibited by elevating fuel pressure from 5.5 to 11.5 MPa at all cases. In detail, the total particles concentration continuously fell at low speed and mid speed-high load cases, but it showed a rose trend when further increase fuel injection pressure at mid speed-low load and high-speed conditions.

Influence of fuel injection parameters of the single and split injection strategies on combustion, performance and particle number emission had been investigated on a gasoline direct injection engine with stoichiometric mixture combustion under medium and low engine operating conditions. The test results showed that the optimal injection timing for single injection strategy was about 290–280 °CA BTDC, and an earlier or a later injection timing could lead to a deterioration of particle number emission. For split injection strategy, the injected parameters also needed to be optimized subtly in order to improve particle number emission. When the inappropriate injected parameters were adopted, particle number emission increased rather than decrease when compared with single injection strategy. Similar to single injection strategy, when the second injection timing of split injection strategy further retarded from 280 °CA BTDC, the particle number emission and brake-specific fuel consumption also started to deteriorate, and the in-cylinder combustion process was delayed and slowed. The optimal first injection timing was about 300 °CA BTDC. When the first injection timing was delayed to 280 °CA BTDC with the second injection timing being 260 °CA BTDC, the particle number emission increased and the shortened interval time between first and second fuel injection might have had a negative effect. The smaller difference of the fuel quantity between the first and the second injection was not good for the improvement of particle number emission and brake-specific fuel consumption, and the best injection proportion was 2:8. Overall, the engine particle number emission could be decreased to some extent, which could reach about 10–30%, by split injection strategy with optimal control parameters at medium and low engine loads.

Spark induced compression ignition (SICI) combined mode combustion can effectively solve the problems existing in homogeneous charge compression ignition (HCCI) combustion, and expand its operation range. The SICI combined combustion of methanol is divided into two combustion stages and has the characteristics of spark ignition (SI) and compression ignition (CI) combustion modes at the same time. This paper studies the SICI combustion mode of methanol from two aspects: simulation and experiment. The simulation results show that with the increase of the wall temperature, it indirectly affected the SICI combined mode combustion by affecting the hot atmosphere in the cylinder, which shortened the whole combustion duration, the SI and CI duration, it had little effect on the combustion ratio of SI and CI. The bench test results show that the methanol engine can obtain stable SICI combined mode combustion mode under the conditions of appropriate intake temperature and suitable ignition timing. From the comparison of three combustion modes of methanol, the results show that the cyclic variability of SICI combustion is the smallest. With the increase of inlet air temperature and the delay of ignition, the BP of SICI combustion at methanol starting point moves backward, the CI combustion rate decreases, but the SI combustion duration changes slightly, and the compression ignition ratio decreases. In the SICI combustion mode of methanol engine, with the increase of intake temperature, NOx emission increases, HC and CO emission decreases. With the advance of ignition timing, CO emission decreases, HC and NOx emission increases.

The first cycle combustion is important for the start process of spark ignition engines and plays an important potential role in the direct-start process. In the experimental work, the effects of initial start conditions, such as initial piston position (IPP), coolant temperature (CT) and fuel injection pressure (FIP), on the combustion and rotation characteristics of the first firing cycle during direct-start process had been investigated. For different IPPs and CTs, the combustion efficiency (CE) increased obviously with the improved excess air coefficient (λ). The most advanced combustion process and fastest heat release velocity appeared for the IPP of 90 and 100°CA. With the λ of 0.7–1.0, the CE was gradually improved for the IPP changed from 40 to 90°CA and the difference was not obvious for the IPPs of 90–120°CA. During the IPP range of 60–110°CA, the engine could get higher peak rotation speed in a relatively wide λ range of 0.6–0.9 and only when the λ was too large or too small, the peak rotation speed decreased obviously. The peak in-cylinder pressure and heat release rate improved, the combustion duration shortened, the heat release velocity increased and the CE enhanced with the CT and FIP improvement. However, the engine still could get bigger peak rotation speed using a relatively smaller λ when the CT and FIP were low. Compared with the two direct-start modes, the IPP range for successful direct-start had a certain overlap and also some differences. The range expanded to 85–130°CA with combined using two direct-start modes and increased and then narrowed with the enhanced CT, but the effect of FIP on it was weak. Controlling the temperature near 70 °C made the successful realization range biggest.

Exhaust gas recirculation (EGR) and lean burn are two common examples of dilution combustion that have been widely applied to improve the performance of gasoline direct injection (GDI) engines. This paper studied influences of air and EGR gas components (CO2, N2, and Ar) on combustion and emission characteristics of a GDI engine, in order to understand their independent effect and provide bases for optimal control of diluents. The results indicated that CO2 dilution showed the strongest influence on combustion process, while Ar showed the weakest. As increasing CO2 addition ratio, the flame development and combustion duration were extended, the combustion center was delayed and the cycle-by-cycle combustion variations was deteriorated significantly. Under the same addition ratio, Ar dilution gave the best fuel economy, while CO2 dilution could more effectively suppress NOx, HC and particulate matter emissions. Moreover, Ar dilution offered the best relationship between fuel economy and NOx emission, followed by N2 and then CO2, and it got the lowest brake specific fuel consumption at the same NOx level. However, CO2 dilution is the most effective method in suppressing particles at the same level of fuel economy.

In this paper, an experimental investigation about the influence of hot EGR addition on the engine combustion, performance and particulate number emission was conducted at a spark-ignition gasoline direct injection (GDI) engine. Meanwhile, the different effects between cooled and hot EGR addition methods were compared and the variations of fuel consumption and particle number emissions under six engine operating conditions with different speeds and loads were analyzed. The research result indicated that increasing hot EGR ratio properly with adjustment of ignition timing could effectively improve the relationship among brake-specific fuel consumption (BSFC), NO x and particle number emissions. When hot EGR ratio increased to 20%, not only BSFC but also the NO x and particle number emissions were reduced, which were about 7%, 87% and 36% respectively. Compared with cooled EGR, the flame development and propagation speeds were accelerated, and cycle-by-cycle combustion variation decreased with hot EGR. Meanwhile, using hot EGR made the engine realize a better relationship among fuel consumption, NO x and particle number emissions. The biggest improvements of BSFC, NO x and particle number emissions were obtained at low-medium speed and medium load engine conditions by hot EGR addition method. While engine speed increased and load decreased, the improvement of engine fuel consumption and emission reduced with hot EGR method.

Increasing compression ratio and using lean burn are two effective techniques for improving engine performance. Methanol has a wide range of sources and is a kind of suitable fuel for a high-compression ratio spark-ignition lean burn engine. Lean burn mainly has a dilution effect, thermal effect and chemical effect. To clarify the influences of different effects and provide guidance for improving composition of dilution gases and applications of this technology, this paper chose Ar, N2 and CO2 as diluents. A spark-ignition methanol engine modified from a diesel engine with a compression ratio of 17.5 was used for the experiments. The results obtained by using methanol spark ignition combustion indicated that at engine speed of 1400 rpm and 25% load, NOx dropped by up to 77.5%, 100% and 100% by Ar, CO2 and N2. Gases with higher specific heat ratio and lower heat capacity represented by Ar exhibited the least adverse effect on combustion and showed a downward break-specific fuel consumption (BSFC) trend. Gas with high specific heat capacity represented by CO2 can decrease NOx and total hydro carbons (THC) emissions at the same time, but the BSFC of CO2 showed the worst trend, followed by N2. Gas affecting the combustion process like CO2 had chemical effect.

Heteroatom-doped carbon materials with expanded interlayer distance have been widely studied as anodes for sodium-ion batteries (SIBs). However, it remains unexplored to further enlarge the interlayer spacing and reveal the influence of heteroatom doping on carbon nanostructures for developing more efficient SIB anode materials. Here, a series of N-rich few-layer graphene (N-FLG) with tuneable interlayer distance ranging from 0.45 to 0.51 nm is successfully synthesized by annealing graphitic carbon nitride (g-C