In order to obtain high power density,energy density and safe energy storage lithium ion batteries(LIB)to meet growing demand for electronic products,oxide cathodes have been widely explored in all-solidstate lithium ...In order to obtain high power density,energy density and safe energy storage lithium ion batteries(LIB)to meet growing demand for electronic products,oxide cathodes have been widely explored in all-solidstate lithium batteries(ASSLB)using sulfide solid electrolyte.However,the electrochemical performances are still not satisfactory,due to the high interfacial resistance caused by severe interfacial instability between sulfide solid electrolyte and oxide cathode,especially Ni-rich oxide cathodes,in charge-discharge process.Ni-rich LiNi0.8Co0.1Mn0.1O2(NCM811)material at present is one of the most key cathode candidates to achieve the high energy density up to 300 Wh kg^-1 in liquid LIB,but rarely investigated in ASSLB using sulfide electrolyte.To design the stable interface between NCM811 and sulfide electrolyte should be extremely necessary.In this work,in view of our previous work,LiNbO3 coating with about 1 wt% content is adopted to improve the interfacial stability and the electrochemical performances of NCM811 cathode in ASSLB using Li10GeP2S12 solid electrolyte.Consequently,LiNbO3-coated NCM811 cathode displays the higher discharge capacity and rate performance than the reported oxide electrodes in ASSLB using sulfide solid electrolyte to our knowledge.展开更多
Nickel-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)is regarded as the promising cathode for lithium-ion batteries(LIBs).However,the challenges such as safety issues and poor cycling performance have seriously hindered...Nickel-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)is regarded as the promising cathode for lithium-ion batteries(LIBs).However,the challenges such as safety issues and poor cycling performance have seriously hindered its commercial applications.In order to overcome these difficulties,there has been extensive research and development of electrolyte modifications for high-energy-density LIBs with Ni-rich cathodes.Herein,this review introduces the research progress based on solvent additives,salt type additives and other electrolytes for LIBs with NCM811cathode materials and discusses how they control the interface stability.In particular,some recommendations for further modification of enhancing electrolyte stability and improving NCM811 electrochemical properties are summarized and proposed,which put forward new design rules for the screening and customizing ideal electrolyte additives for high performance NCM811 cathode-based LIBs.展开更多
Doping and coating are frequently employed for the improvement of the properties of Ni-rich NCM materials.In this work,we prepared stable LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)materials modified withY_(2)O_(3)via a w...Doping and coating are frequently employed for the improvement of the properties of Ni-rich NCM materials.In this work,we prepared stable LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)materials modified withY_(2)O_(3)via a wet chemical method.In order to investigate the action mechanism ofY_(2)O_(3)on NCM811,we analyzed the micro structures using X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).Also,to study the electrochemical performances,we conducted a charge/discharge test and cyclic voltammetry.Our results show thatY_(2)O_(3)modified NCM811 materials have good thermal stability,and proper content ofY_(2)O_(3)can effectively prevent the materials from damaging and significantly improve the electrochemical properties of the materials.Particularly,1%Y2 O3 modified NCM811 material show much better cycling performance than other samples.During cycling at 1.0 C the 1%Y2 O3 modified NCM811 shows capacity retention of 90.1%after 100 cycles,which is higher than 69.4%for pristine NMC811.We examined the microstructures of the materials before and after circulation.Using the SEM results,we conclude that structural changes are among the key factors that lead to the degradation of the electrochemical properties of materials.展开更多
Atomic layer deposition(ALD)technology has been adopted to obtain the ultrathin coating layer on the surface of LiNi_(x)Co_(y)Mn_(z)O_(2)(NCM)cathode materials.However,the as-reported coating materials usually form de...Atomic layer deposition(ALD)technology has been adopted to obtain the ultrathin coating layer on the surface of LiNi_(x)Co_(y)Mn_(z)O_(2)(NCM)cathode materials.However,the as-reported coating materials usually form dense film layers and present low electronic conductivity,leading to poor electrochemical kinetics.Herein,the ultrafine Pd nanoparticles(~5 nm)with superior electronic conductivity are successfully deposited on the surface of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)particles by ALD technology.Benefiting from its high electrical conductivity,intrinsic electrochemical inertia to Li+and HF,unique point coating,and the interfacial Pd-O bond,the coating of ultrafine Pd nanoparticles significantly weakens the electrochemical polarization and enhances the rate capability of NCM811 cathode.The capacity retention ratio at 1 C after 100 cycles reaches 84.6%,and the capacity of 153.5 mA·h·g^(−1) is realized at 5 C.Further research finds that the battery with the coating layer of 5 deposition cycles has a better electrochemical performance than the batteries with 2 and 8 deposition cycles.This work enriches the application of ALD technology in the surface modification of electrode materials and broadens the mind of electrochemical performance enhancement.展开更多
With high reversible capacities of more than 200 mAh/g,Ni-rich layered oxides Li[Ni_(x)Co_(y)Mn_(1–x–y)]O_(2)(x≥0.6)serve as the most promising cathode materials for lithium-ion batteries(LIBs).However,the anisotro...With high reversible capacities of more than 200 mAh/g,Ni-rich layered oxides Li[Ni_(x)Co_(y)Mn_(1–x–y)]O_(2)(x≥0.6)serve as the most promising cathode materials for lithium-ion batteries(LIBs).However,the anisotropic lattice volume changes linked to theirα-NaFeO_(2)structured crystal grains bring about poor cycle performances for conventionally produced NCM materials.To deal with these issue,single-crystalµm-sized LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)rods was synthesized by a hydrothermal method.Compared with conventional synthesis methods,these LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)rods were calcined at a low temperature with excessive lithium sources,which not only reduces the sintering temperature but also ensures the mono-dispersed micrometer-scaled particle distribution.When used as the cathode material for LIBs,the as-prepared LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2),with ordered layered-structure and low degree of cation mixing,shows excellent electrochemical performances.When sintered at 750°C with 50%Li-excess,the cathode material delivered an initial discharge capacity of 226.9 mAh/g with Coulombic efficiency of 91.2%at 0.1 C(1 C=200 mA/g)in the voltage range of 2.8‒4.3 V.When charge-discharged at 1 C for 100 cycles,discharge capacity of 178.1 mAh/g with the capacity retention of 95.1%are still obtained.The cycling stability at high cut-off voltage is also outstanding.These superior electrochemical properties should be related to the monodispersed micron scaled morphology which not only decreases the contact area between electrode and electrolyte but also mitigates the formation of microcracks.This low-temperature strategy of synthesizing single-crystal LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)rods should be able to provide a feasible method for synthesizing other single-crystal Ni-rich cathode materials with excellent electrochemical performances for LIB.展开更多
Lithium-ion batteries(LIBs)featuring a Ni-rich cathode exhibit increased specific capacity,but the establishment of a stable interphase through the implementation of a functional electrolyte strategy remains challengi...Lithium-ion batteries(LIBs)featuring a Ni-rich cathode exhibit increased specific capacity,but the establishment of a stable interphase through the implementation of a functional electrolyte strategy remains challenging.Especially when the battery is operated under high temperature,the trace water present in the electrolyte will accelerate the hydrolysis of the electrolyte and the resulting HF will further erode the interphase.In order to enhance the long-term cycling performance of graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)LIBs,herein,Tolylene-2,4-diisocyanate(TDI)additive containing lone-pair electrons is employed to formulate a novel bifunctional electrolyte aimed at eliminating H_(2)O/HF generated at elevated temperature.After 1000 cycles at 25℃,the battery incorporating the TDI-containing electrolyte exhibits an impressive capacity retention of 94%at 1 C.In contrast,the battery utilizing the blank electrolyte has a lower capacity retention of only 78%.Furthermore,after undergoing 550 cycles at 1 C under45℃,the inclusion of TDI results in a notable enhancement of capacity,increasing it from 68%to 80%.This indicates TDI has a favorable influence on the cycling performance of LIBs,especially at elevated temperatures.The analysis of the film formation mechanism suggests that the lone pair of electrons of the isocyanate group in TDI play a crucial role in inhibiting the generation of H_(2)O and HF,which leads to the formation of a thin and dense interphase.The existence of this interphase is thought to substantially enhance the cycling performance of the LIBs.This work not only improves the performance of graphite/NCM811 batteries at room temperature and high temperature by eliminating H_(2)O/HF but also presents a novel strategy for advancing functional electrolyte development.展开更多
基金financially supported partly by the National Key Research and Development Program of China (2018YFB0104302)NSFC (21503148)Major Programs of the Innovation Driven Plan of Guilin (No. 20160203)
文摘In order to obtain high power density,energy density and safe energy storage lithium ion batteries(LIB)to meet growing demand for electronic products,oxide cathodes have been widely explored in all-solidstate lithium batteries(ASSLB)using sulfide solid electrolyte.However,the electrochemical performances are still not satisfactory,due to the high interfacial resistance caused by severe interfacial instability between sulfide solid electrolyte and oxide cathode,especially Ni-rich oxide cathodes,in charge-discharge process.Ni-rich LiNi0.8Co0.1Mn0.1O2(NCM811)material at present is one of the most key cathode candidates to achieve the high energy density up to 300 Wh kg^-1 in liquid LIB,but rarely investigated in ASSLB using sulfide electrolyte.To design the stable interface between NCM811 and sulfide electrolyte should be extremely necessary.In this work,in view of our previous work,LiNbO3 coating with about 1 wt% content is adopted to improve the interfacial stability and the electrochemical performances of NCM811 cathode in ASSLB using Li10GeP2S12 solid electrolyte.Consequently,LiNbO3-coated NCM811 cathode displays the higher discharge capacity and rate performance than the reported oxide electrodes in ASSLB using sulfide solid electrolyte to our knowledge.
基金financially supported by the National Natural Science Foundation of China(Nos.51971090,U21A20311)。
文摘Nickel-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)is regarded as the promising cathode for lithium-ion batteries(LIBs).However,the challenges such as safety issues and poor cycling performance have seriously hindered its commercial applications.In order to overcome these difficulties,there has been extensive research and development of electrolyte modifications for high-energy-density LIBs with Ni-rich cathodes.Herein,this review introduces the research progress based on solvent additives,salt type additives and other electrolytes for LIBs with NCM811cathode materials and discusses how they control the interface stability.In particular,some recommendations for further modification of enhancing electrolyte stability and improving NCM811 electrochemical properties are summarized and proposed,which put forward new design rules for the screening and customizing ideal electrolyte additives for high performance NCM811 cathode-based LIBs.
基金Project supported by Hebei Province Major Scientific and Technological Achievements Transformation Project(20284401Z)。
文摘Doping and coating are frequently employed for the improvement of the properties of Ni-rich NCM materials.In this work,we prepared stable LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)materials modified withY_(2)O_(3)via a wet chemical method.In order to investigate the action mechanism ofY_(2)O_(3)on NCM811,we analyzed the micro structures using X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).Also,to study the electrochemical performances,we conducted a charge/discharge test and cyclic voltammetry.Our results show thatY_(2)O_(3)modified NCM811 materials have good thermal stability,and proper content ofY_(2)O_(3)can effectively prevent the materials from damaging and significantly improve the electrochemical properties of the materials.Particularly,1%Y2 O3 modified NCM811 material show much better cycling performance than other samples.During cycling at 1.0 C the 1%Y2 O3 modified NCM811 shows capacity retention of 90.1%after 100 cycles,which is higher than 69.4%for pristine NMC811.We examined the microstructures of the materials before and after circulation.Using the SEM results,we conclude that structural changes are among the key factors that lead to the degradation of the electrochemical properties of materials.
基金This work was supported by the National Natural Science Foundation of China(Grant No.5210130199 and 52072298)China Postdoctoral Science Foundation(Grant No.2021M692596)+4 种基金Innovation Ability Strengthening Foundation Plan of Xi’an(Grant No.21XJZZ0043)Young Talent Fund of University Association for Science and Technology in Shaanxi of China(Grant No.20200418)Open Foundation of Key Laboratory of Green Preparation and Functionalization for Inorganic Materials(Grant No.202002)the Local Special Service Program Funded by Education Department of Shaanxi Provincial Government(Grant No.19JC031)Natural Science Foundation of Shaanxi(Grant No.2020JC-41 and 2021TD-15).
文摘Atomic layer deposition(ALD)technology has been adopted to obtain the ultrathin coating layer on the surface of LiNi_(x)Co_(y)Mn_(z)O_(2)(NCM)cathode materials.However,the as-reported coating materials usually form dense film layers and present low electronic conductivity,leading to poor electrochemical kinetics.Herein,the ultrafine Pd nanoparticles(~5 nm)with superior electronic conductivity are successfully deposited on the surface of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)particles by ALD technology.Benefiting from its high electrical conductivity,intrinsic electrochemical inertia to Li+and HF,unique point coating,and the interfacial Pd-O bond,the coating of ultrafine Pd nanoparticles significantly weakens the electrochemical polarization and enhances the rate capability of NCM811 cathode.The capacity retention ratio at 1 C after 100 cycles reaches 84.6%,and the capacity of 153.5 mA·h·g^(−1) is realized at 5 C.Further research finds that the battery with the coating layer of 5 deposition cycles has a better electrochemical performance than the batteries with 2 and 8 deposition cycles.This work enriches the application of ALD technology in the surface modification of electrode materials and broadens the mind of electrochemical performance enhancement.
基金the National Science Foundation of China(grant No.21271145)the National Science Foundation of Hubei Province(grant No.2015CFB537)for the financial support for this investigation.
文摘With high reversible capacities of more than 200 mAh/g,Ni-rich layered oxides Li[Ni_(x)Co_(y)Mn_(1–x–y)]O_(2)(x≥0.6)serve as the most promising cathode materials for lithium-ion batteries(LIBs).However,the anisotropic lattice volume changes linked to theirα-NaFeO_(2)structured crystal grains bring about poor cycle performances for conventionally produced NCM materials.To deal with these issue,single-crystalµm-sized LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)rods was synthesized by a hydrothermal method.Compared with conventional synthesis methods,these LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)rods were calcined at a low temperature with excessive lithium sources,which not only reduces the sintering temperature but also ensures the mono-dispersed micrometer-scaled particle distribution.When used as the cathode material for LIBs,the as-prepared LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2),with ordered layered-structure and low degree of cation mixing,shows excellent electrochemical performances.When sintered at 750°C with 50%Li-excess,the cathode material delivered an initial discharge capacity of 226.9 mAh/g with Coulombic efficiency of 91.2%at 0.1 C(1 C=200 mA/g)in the voltage range of 2.8‒4.3 V.When charge-discharged at 1 C for 100 cycles,discharge capacity of 178.1 mAh/g with the capacity retention of 95.1%are still obtained.The cycling stability at high cut-off voltage is also outstanding.These superior electrochemical properties should be related to the monodispersed micron scaled morphology which not only decreases the contact area between electrode and electrolyte but also mitigates the formation of microcracks.This low-temperature strategy of synthesizing single-crystal LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)rods should be able to provide a feasible method for synthesizing other single-crystal Ni-rich cathode materials with excellent electrochemical performances for LIB.
基金financially supported by the Scientific and Technological Plan Projects of Guangzhou City(202103040001),P.R.Chinathe Project of Science and Technology Department of Henan Province(222102240074)the Key Research Programs of Higher Education Institutions of Henan Province(24B150009)。
文摘Lithium-ion batteries(LIBs)featuring a Ni-rich cathode exhibit increased specific capacity,but the establishment of a stable interphase through the implementation of a functional electrolyte strategy remains challenging.Especially when the battery is operated under high temperature,the trace water present in the electrolyte will accelerate the hydrolysis of the electrolyte and the resulting HF will further erode the interphase.In order to enhance the long-term cycling performance of graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)LIBs,herein,Tolylene-2,4-diisocyanate(TDI)additive containing lone-pair electrons is employed to formulate a novel bifunctional electrolyte aimed at eliminating H_(2)O/HF generated at elevated temperature.After 1000 cycles at 25℃,the battery incorporating the TDI-containing electrolyte exhibits an impressive capacity retention of 94%at 1 C.In contrast,the battery utilizing the blank electrolyte has a lower capacity retention of only 78%.Furthermore,after undergoing 550 cycles at 1 C under45℃,the inclusion of TDI results in a notable enhancement of capacity,increasing it from 68%to 80%.This indicates TDI has a favorable influence on the cycling performance of LIBs,especially at elevated temperatures.The analysis of the film formation mechanism suggests that the lone pair of electrons of the isocyanate group in TDI play a crucial role in inhibiting the generation of H_(2)O and HF,which leads to the formation of a thin and dense interphase.The existence of this interphase is thought to substantially enhance the cycling performance of the LIBs.This work not only improves the performance of graphite/NCM811 batteries at room temperature and high temperature by eliminating H_(2)O/HF but also presents a novel strategy for advancing functional electrolyte development.
