Recent progress on the recycling technology of Li-ion batteries

Lithium-ion batteries(LIBs)have been widely applied in portable electronic devices and electric vehicles.With the booming of the respective markets,a huge quantity of spent LIBs that typically use either LiFePO_(4) or Li N_(x)Co_(y)Mn_(z)O_(2) cathode materials will be produced in the very near future,imposing significant pressure for the development of suitable disposal/recycling technologies,in terms of both environmental protection and resource reclaiming.In this review,we firstly do a comprehensive summary of the-state-of-art technologies to recycle Li N_(x)Co_(y)Mn_(z)O_(2) and LiFePO_(4)-based LIBs,in the aspects of pretreatment,hydrometallurgical recycling,and direct regeneration of the cathode materials.This closed-loop strategy for cycling cathode materials has been regarded as an ideal approach considering its economic benefit and environmental friendliness.Afterward,as for the exhausted anode materials,we focus on the utilization of exhausted anode materials to obtain other functional materials,such as graphene.Finally,the existing challenges in recycling the LiFePO_(4) and Li N_(x)Co_(y)Mn_(z)O_(2) cathodes and graphite anodes for industrial-scale application are discussed in detail;and the possible strategies for these issues are proposed.We expect this review can provide a roadmap towards better technologies for recycling LIBs,shed light on the future development of novel battery recycling technologies to promote the environmental benignity and economic viability of the battery industry and pave way for the large-scale application of LIBs in industrial fields in the near future.

Paraffin/SiC as a Novel Composite Phase-Change Material for a Lithium-Ion Battery Thermal Management System

A lithium-ion battery thermal management system has always been a hot spot in the battery industry. In this study, a novel high-thermal-conductivity composite phase-change material(CPCM) made by paraffin wax and silicon was adopted to facilitate heat transfer. Moreover, high resistance or even insulation of CPCM is capable of preventing short circuits between the cells. The heat transfer mechanism of CPCMs was determined under a scanning electron microscope. A thermogravimetric analyzer was employed to determine the thermal stability. A diff erential scanning calorimeter was used to explore the thermophysical properties of the composite samples. By comparing the results of the experiment, it was reported that under the silicon carbide content of 5%, the parameters were better than others. The phase-change enthalpy of CPCM was 199.4 J/g, the leakage rate of liquid was 4.6%, and the melting point was 53.6℃. To verify the practicality of CPCM, a three-dimensional layered battery pack model was built in the COMSOL Multiphysics software. By simulating the thermal runaway inside the battery packs of various materials, it was reported that the addition of CPCM significantly narrowed the temperature range of the battery pack from 300–370 to 303–304 K. Therefore, CPCM can eff ectively increase the rate of heat transfer to prevent the chain of thermal runaway reactions. It also enables the battery pack to run at a stable temperature.

Construction of Phosphorus-Functionalized Multichannel Carbon Interlayers for Dendrite-Free Metallic Zn Anodes

Zn metal anodes are usually subject to grave dendrite growth during platting/stripping,which dramatically curtails the lifespan of aqueous Zn-ion batteries and capacitors.To address above problems,in our work,a novel phosphorus-functionalized multichannel carbon interlayer was designed and covered on Zn anodes.The results demonstrated that the multichannel structure combined with the three-dimensional meshy skeleton can provide more sufficient space for Zn deposition,thereby effectively inhibiting the growth of zinc dendrites.Meanwhile,theoretical calculations also confirmed that the P-C and P=O functional groups from phosphorus-functionalized multichannel carbon interlayer have the decisive influence in reducing the zinc nucleation potential and depositing uniformly zinc.Concretely,the symmetrical battery assembled with phosphorus-functionalized multichannel carbon interlayer-covered Zn anodes possessed a long lifetime of 3300 h at 2 mA cm^(-2)with 1 mAh cm^(-2).Furthermore,the full cell with activated carbon cathodes exhibited a high specific capacity of 80.5 mAh g^(-1)and outstanding cycling stability without capacity decay after 15000 cycles at a high current density of 5 A g^(-1).The superior electrochemical performance exceeded that of most reported papers.Consequently,our synthesized zincophilic interlayer with the unique structure has superior prospects for application in stabilizing zinc anodes and prolonging the lifespan of batteries.

Reversible and irreversible heat generation of NCA/Si–C pouch cell during electrochemical energy-storage process

To meet the requirements of electronic vehicles(EVs) and hybrid electric vehicles(HEVs),the high energy density Li Ni_(0.8) Co_(0.15) Al_(0.05) O_2(NCA) cathode and Si–C anode have attracted more attention.Here we report the thermal behaviors of NCA/Si–C pouch cell during the charge/discharge processes at different current densities.The total heat generations are derived from the surface temperature change during electrochemical Li+insertion/extraction in adiabatic surrounding.The reversible heat is determined by the entropic coefficients,which are related with open-circuit voltage at different temperatures; while the irreversible heat is determined by the internal resistance,which can be obtained via V–I characteristic,electrochemical impedance spectroscopy and hybrid pulse power characterization(HPPC).During the electrochemical process,the reversible heat contributes less than 10% to total heat generation; and the heat generated in charge process is less than that in discharge process.The results of thermal behaviors analyses are conducive to understanding the safety management and paving the way for building a reliable thermal model of high energy density lithium ion battery.

Influence of carbon sources on the performance of carbon-coated nano-silicon

Silicon-based material is an important anode material for next-generation lithium-ion batteries.In order to overcome its shortcomings,carbon coating is often employed to improve the electrochemical performance.However,the carbon source,carbon content,and different contact and mixing schemes between carbon sources and silicon are all complex factors and need to be clarified.In this study,nano-silicon is coated by the chemical vapor deposition method using different carbon sources,such as acetylene,methane,propane,and propylene.Carbon content after coating is designed to stay at the same level to reduce the experimental error.Results show the sample with higher conductivity provides higher cycle performance.Propylene is the best choice of the four carbon sources studied in this work.These results indicate that the selection of the carbon source is an important factor that plays a significant role in electrochemical performance.

Aplication of Corncob-Based Activated Carbon as Electrode Material for Electric Double-Layer Capacitors

To investigate the influence of expansion pretreatment for materials on carbon structure, activated carbons （ACs） were prepared from corncob with/without expansion pretreatment by KOH activation, the structure properties of which were determined based on N2 adsorption isotherm at 77 K. The results show that the expansion pretreatment for corncobs is beneficial to the preparation of ACs with high surface area. The specific surface area of the AC derived from corncob with expansion pretreatment （AC-1） is 32.5% larger than that without expansion pretreatment （AC-2）. Furthermore, to probe the potential application of corncob-based ACs in electric double-layer capacitor （EDLC）, the prepared ACs were used as electrode materials to assemble EDLC, and its electrochemical performance was investi- gated. The results indicate that the specific capacitance of AC-I is 276 F/g at 50 mA/g, which increases by 27% com- pared with that of AC-2 （217 F/g）. As electrode materials, AC-1 presents a better electrochemical performance than AC-2, including a higher voltage maintenance ratio and a lower leakage current.

Optimized Method for Real-time Texture Reconstruction with RGB-D Camera

With the appearance of RGB-D camera, the field of three-dimensional (3D) reconstruction receives more and more attention. In this paper, we present an optimization approach to produce high-quality textured 3D models based on the real-time 3D reconstruction system. The resulting models of real-time texture reconstruction often suffer from blurring, ghosting, and other artifacts. Our approach addresses this texture quality problem using blur detection and an optimized weight function. Experimental results demonstrate that our approach can improve the quality of textured 3D models by reducing the blur and ghosts on the model surface. © 2017, Tianjin University and Springer-Verlag GmbH Germany.

Internal field study of 21700 battery based on long-life embedded wireless temperature sensor

The safety of lithium-ion batteries is an essential concern where instant and accurate temperature sensing is critical.It is generally desired to put sensors inside batteries for instant sensing.However,the transmission of internal measurement outside batteries without interfering their normal state is a non-trivial task due to the harsh electrochemical environment,the particular packaging structures and the intrinsic electromagnetic shielding problems of batteries.In this work,a novel in-situ temperature sensing framework is proposed by incorporating temperature sensors with a novel signal transmission solution.The signal transmission solution uses a self-designed integrated-circuit which modulates the internal measurements outside battery via its positive pole without package breaking.Extensive experimental results validate the noninterference properties of the proposed framework.Our proposed in-situ temperature measurement by the self-designed signal modulation solution has a promising potential for in-situ battery health monitoring and thus promoting the development of smart batteries.

Fluorinated graphite nanosheets for ultrahigh-capacity lithium primary batteries

For better performances of Ni-based catalysts at low temperatures,Ni/SiC catalyst doped with a little amount of additive La was successfully prepared.The catalytic CO methanation activity tests showed that 3%La-Ni/SiC catalyst was excellent at a low reaction temperature(95.9%CO conversion and 85.1%CH4 selectivity at250℃)with a superior stability compared with Ni/SiC(3.4%CO conversion and 0%CH4 selectivity at 250℃).This can be attributed to that the addition of La can markedly improve the dispersibility of active metal Ni and reduce the particle sizes of Ni nanoparticles or clusters,and can also regulate the interaction between active components and supports.Moreover,the high thermal conductivity and thermal stability could avoid the generation of hot spots in the catalyst bed.These results will promote the development of highly active Ni-based catalysts for the low-temperature methanation reaction.

Enhancing the reversible capacity and cycle stability of lithium-ion batteries with Li-compensation material Li_(6)CoO_(4)

High-capacity anode materials,such as SiO and Si/C,are considered promising candidates for high-energydensity lithium-ion batteries.However,the low initial Coulombic efficiency of these anode materials induced by side reactions(forming Li_(2)O and lithium silicate)and the formation of solid electrolyte interface film reduces the active Liions and causes low-discharge capacity.Adding a Li-compensation material in the cathode or anode is an effective strategy to overcome this problem.The most used Li-compensation material is the stabilized lithium metal powder.However,this strategy has high safety risks,high costs,and is challenging to quantify.Herein,the Li-compensation material of Li_(6)CoO_(4) is synthesized and investigated.The preparation conditions,stability in the air,delithiation mechanism,and structural transformation are analyzed and discussed.Electrochemical tests reveal that the discharge capacity and capacity retention of the full pouch cells(3-Ah)with Li_(6)CoO_(4) additive is significantly improved.Also,the reason for such improvement is investigated.This work provides an effective strategy of Li-compensating technology to enhance the electrochemical performance of lithium-ion batteries.

Thickness evolution of commercial Li-ion pouch cells with siliconbased composite anodes and NCA cathodes

It is significant to monitor the thickness change of commercial Li-ion pouch cells that are assembled from Si-based electrodes and layered cathodes since the volume variation is critically linked with kinetic reaction mechanism and chemomechanical degradation. In this work, the single-point and full-field measurements are conducted on the thickness evolution of Si Ox/Cgraphite/lithium nickel-cobalt-aluminum oxide(Si Ox-G/NCA) batteries. It is found that an abnormal overshoot that has been rarely observed in the previous studies appears at the beginning of discharge, which is believed to be the combined results between the rapid expansion of NCA and the contraction of graphite related to the state of charge(SOC). Compared with the results of single-point measurement, the spatial displacement distribution obtained from three-dimensional(3D) scanning suggests the full-field thickness evolution of the entire cell scale, which is more feasible and efficient to provide full-field information for supporting pouch cell design and pack integration.