In order to achieve better Na storage performance, most layered oxide positive electrode materials contain toxic and expensive transition metals Ni and/or Co, which are also widely used for lithium-ion batteries. Here...In order to achieve better Na storage performance, most layered oxide positive electrode materials contain toxic and expensive transition metals Ni and/or Co, which are also widely used for lithium-ion batteries. Here we report a new quaternary layered oxide consisting of Cu, Fe, Mn, and Ti transition metals with O3-type oxygen stacking as a positive electrode for room-temperature sodium-ion batteries. The material can be simply prepared by a high-temperature solidstate reaction route and delivers a reversible capacity of 94 m Ah/g with an average storage voltage of 3.2 V. This paves the way for cheaper and non-toxic batteries with high Na storage performance.展开更多
Magnesium-based rechargeable batteries might be an interesting future alternative to lithium-based batteries. It is so far well known that Mg2+ ion insertion into ion-transfer hosts proceeds slowly compared with Li+, ...Magnesium-based rechargeable batteries might be an interesting future alternative to lithium-based batteries. It is so far well known that Mg2+ ion insertion into ion-transfer hosts proceeds slowly compared with Li+, so it is necessary to realize fast Mg2+ transport in the host in addition to other requirements as practical cathode materials for magnesium batteries. Positive electrode materials based on inorganic transition-metal oxides, sulfides, and borides are the only ones used up to now to insert magnesium ions. In this paper, the available results of research on materials suitable as possible, for secondary magnesium batteries, are reviewed.展开更多
In the present paper, multi-walled carbon nanotubes（MWCNTs） are successfully assembled on graphite felt（GF） using sucrose pyrolysis method for the first time. The in situ formed pyrolytic carbon is chosen as the b...In the present paper, multi-walled carbon nanotubes（MWCNTs） are successfully assembled on graphite felt（GF） using sucrose pyrolysis method for the first time. The in situ formed pyrolytic carbon is chosen as the binder because it is essentially carbon materials as well as CNTs and GF which has a natural tendency to achieve high bonding strength and low contact resistance. The MWCNTs/GF electrode is demonstrated to increase surface area, reduce polarization, lower charge transfer resistance and improve energy conversion efficiency comparing with GF. This excellent electrochemical performance is mainly ascribed to the high electro-catalytic activity of MWCNTs and increasing surface area.展开更多
The reactivity between charged Li(Li_(0.115)Mn_(0.529)Ni_(0.339)Al_(0.017))O_(2)(Li-rich),single crystal Li(Ni_(0.8)Mn_(0.1)Co_(0.1))O_(2)(SC-NMC811),LiFePO_(4)(LFP) and LiMn_(0.8)Fe_(0.2)PO_(4)(LMFP) positive electro...The reactivity between charged Li(Li_(0.115)Mn_(0.529)Ni_(0.339)Al_(0.017))O_(2)(Li-rich),single crystal Li(Ni_(0.8)Mn_(0.1)Co_(0.1))O_(2)(SC-NMC811),LiFePO_(4)(LFP) and LiMn_(0.8)Fe_(0.2)PO_(4)(LMFP) positive electrodes at different states of charge(SOCs) and traditional carbonate-based electrolyte at elevated temperatures is systematically studied using accelerating rate calorimetry(ARC).The results show that the SOC greatly affects the thermal stability of the Li-rich and SC-NMC811 when traditional carbonate-based electrolyte is used.Although an increase in the SOC increases the energy density of lithium-ion cells,it also increases the reactivity between charged Li-rich and SC-NMC811 samples with electrolyte at elevated temperatures.In comparison with SC-NMC811,the Li-rich samples are much more stable at elevated temperatures,and the latter have higher specific capacity.SC-NMC811 samples are less reactive than traditional polycrystalline NMC811.Both LFP and LMFP samples show excellent thermal stability at elevated temperatures.The substitution of Fe by Mn in the olivine series positive materials does not impact the reactivity with electrolyte.展开更多
To achieve stable positive electrode for promoting the overall electrochemical performance of Al batteries(ABs),here novel cobalt boride(CoB)nanoclusters are synthesized to construct composite electrodes with few-laye...To achieve stable positive electrode for promoting the overall electrochemical performance of Al batteries(ABs),here novel cobalt boride(CoB)nanoclusters are synthesized to construct composite electrodes with few-layer graphene(FLG).Due to the presence of amorphous channels in the employed CoB nanoclusters,the ABs with FLG/CoB composite positive electrodes exhibit high rate.capability and both mechanical and electrochemical stability in the ABs.With assistance of in situ scanning electron microscopy(SEM),the observation results suggest that the positive electrode of CoB nanoclusters holds almost ignorable volume variation upon electrochemical processes,which substantially alleviates the massive electrode expansion induced by the anion intercalation in the composite positive electrode.Interestingly,the composite positive electrodes provide stable reversible energy storage capability within a broadened temperature range(-30-60℃),promising a novel strategy to design advanced ABs positive electrodes with enhanced overall energy storage performance.展开更多
In a steady-state plasma,the loss rate of plasma particles to the chamber wall and surfaces in contact with plasma is balanced by the ionization rate of background neutrals in the hot-filament discharges.The balance b...In a steady-state plasma,the loss rate of plasma particles to the chamber wall and surfaces in contact with plasma is balanced by the ionization rate of background neutrals in the hot-filament discharges.The balance between the loss rate and ionization rate of plasma particles(electrons and ions)maintains quasi-neutrality of the bulk plasma.In the presence of an external perturbation,it tries to retain its quasi-neutrality condition.In this work,we studied how the properties of bulk plasma are affected by an external DC potential perturbation.An auxiliary biased metal disk electrode was used to introduce a potential perturbation to the plasma medium.A single Langmuir probe and an emissive probe,placed in the line of the discharge axis,were used for the characterization of the bulk plasma.It is observed that only positive bias to the auxiliary metal disk increases the plasma potential,electron temperature,and plasma density but these plasma parameters remain unaltered when the disk is biased with a negative potential with respect to plasma potential.The observed plasma parameters for two different-sized,positively as well as negatively biased,metal disks are compared and found inconsistent with the existing theoretical model at large positive bias voltages.The role of the primary energetic electrons population in determining the plasma parameters is discussed.The experimentally observed results are qualitatively explained on the basis of electrostatic confinement arising due to the loss of electrons to a biased metal disk electrode.展开更多
Aluminum batteries are attractive in electrochemical energy storage due to high energy density and lowcost aluminum,while the energy density is limited for the lack of favorable positive electrode materials to match a...Aluminum batteries are attractive in electrochemical energy storage due to high energy density and lowcost aluminum,while the energy density is limited for the lack of favorable positive electrode materials to match aluminum negative electrodes.Tellurium positive electrode is intrinsically electrically conductive among chalcogen and holds high theoretical specific capacity(1260.27 mAh g^(-1)) and discharge voltage plateau(~1,5 V).However,the chemical and electrochemical dissolution of Te active materials results in the low material utilization and poor cycling stability.To enhance the electrochemical performance,herein a nitrogen doped porous carbon(N-PC) is derived from zeolite imidazolate framework(ZIF-67)as an effective tellurium host to suppress the undesired shuttle effect.In order to inhibit the volume expansion of N-PC during the charge/discharge process,the reduced graphene oxide(rGO) nanosheets are introduced to form a stable host materials(N-PC-rGO) for stabilizing Te.The physical encapsulation and chemical confinement to soluble tellurium species are achieved.N-PC-rGO-Te positive electrode exhibits an improved initial specific capacity and long-term cycling performance at a current density of 500 mA g^(-1)(initial specific capacity:935.5 mAh g^(-1);after 150 cycles:467.5 mAh g^(-1)), highlighting a promising design strategy for inhibiting chemical and electrochemical dissolution of Te.展开更多
The effect of operating conditions on the aluminium content of Ni-Al alloy deposit and the catalytic function of NaF on electrodeposition in the nonaqueous solution containing aluminium are investigated.The results in...The effect of operating conditions on the aluminium content of Ni-Al alloy deposit and the catalytic function of NaF on electrodeposition in the nonaqueous solution containing aluminium are investigated.The results indicate that the plated aluminuim content will be increased with the rise of current density in a given range.When the current density is 2.5A/dm 2,nickle aluminium alloy containing 13.1 wt% aluminium will be deposited.The plated aluminium content will be increased by 2wt% as 0.1mol/L NaF is added to the bath.展开更多
Low specific capacitances and/or limited working potential(≤4.5 V).of the prevalent carbon-based positive electrodes as the inborn bottleneck seriously hinder practical advancement of lithium-ion capacitors.Thus,brea...Low specific capacitances and/or limited working potential(≤4.5 V).of the prevalent carbon-based positive electrodes as the inborn bottleneck seriously hinder practical advancement of lithium-ion capacitors.Thus,breakthroughs in enhancement of both specific capacitances and upper cutoff potentials are enormously significant for high-energy density lithium-ion capacitors.Herein,we first meticulously design and scalably fabricate a commercializable fluorine-doped porous carbon material with competitive tap density,large active surface,appropriate aperture distribution,and promoted affinity with the electrolyte,rendering its abundant electroactive inter-/surface and rapid PF_(6)^(-)transport.Theoretical calculations authenticate that fluorine-doped porous carbon possesses lower PF_(6)^(-)adsorption energy and stronger interaction with PF_(6)^(-).Thanks to the remarkable structural/compositional superiority,when served as a positive electrode toward lithium-ion capacitors,the commercial-level fluorine-doped porous carbon showcases the record-breaking electrochemical properties within a wider working window of 2.5-5.0 V(vs Li/Li^(+))in terms of high-rate specific capacitances and long-duration stability,much superior to commercial activated carbon.More significantly,the 4.5 V-class graphite//fluorine-doped porous carbon lithium-ion capacitors are first constructed and manifest competitive electrochemical behaviors with long-cycle life,modest polarization,and large energy density.Our work provides a commendable positive paradigm and contributes a major step forward in next-generation lithium-ion capacitors and even other high-energy density metal-ion capacitors.展开更多
The Ni-rich Li[Ni0.6Co0.2Mn0.2]O2 surface has been modified with H3PO4. After coating at 80 ℃, the products were heated further at a moderate temperature of 500 ℃ in air, when the added H3PO4 transformed to Li3PO4 a...The Ni-rich Li[Ni0.6Co0.2Mn0.2]O2 surface has been modified with H3PO4. After coating at 80 ℃, the products were heated further at a moderate temperature of 500 ℃ in air, when the added H3PO4 transformed to Li3PO4 after reacting with residual LiOH and Li2CO3 on the surface. A thin and uniform smooth nanolayer （〈 10 nm） was observed on the surface of Li[Ni0.6Co0.2Mn0.2]O2 as confirmed by transmission electron microscopy （TEM）. Time-of-flight secondary ion mass spectroscopic （ToF-SIMS） data exhibit the presence of LIP＋, LiPO-, and Li2PO2＋ fragments, indicating the formation of the Li3PO4 coating layer on the surface of the Li[Ni0.6Co0.2Mn0.2]O2. As a result, the amounts of residual lithium compounds, such as LiOH and Li2CO3, are significantly reduced. As a consequence, the LigPO4-coated Li[Ni0.6Co0.2Mn0.2]O2 exhibits noticeable improvement in capacity retention and rate capability due to the reduction of residual LiOH and Li2CO3. Further investigation of the extensively cycled electrodes by X-ray diffraction （XRD）, TEM, and ToF-SIMS demonstrated that the LiBPO4 coating layers have multi-functions： Absorption of water in the electrolyte that lowers the HF level, HF scavenging, and protection of the active materials from deleterious side reactions with the electrolyte during extensive cycling, enabling high capacity retention over 1,000 cycles.展开更多
Graphite as a positive electrode material of dual ion batteries(DIBs)has attracted tremendous attentions for its advantages including low lost,high working voltage and high energy density.However,very few literatures ...Graphite as a positive electrode material of dual ion batteries(DIBs)has attracted tremendous attentions for its advantages including low lost,high working voltage and high energy density.However,very few literatures regarding to the real-time observation of anion intercalation behavior and surface evolution of graphite in DIBs have been reported.Herein,we use in situ atomic force microscope(AFM)to directly observe the intercalation/de-intercalation processes of PF6^-in graphite in real time.First,by measuring the change in the distance between graphene layers during intercalation,we found that PF6^-intercalates in one of every three graphite layers and the intercalation speed is measured to be 2μm-min^-1.Second,graphite will wrinke and suffer structural damnages at high voltages,along with severe electrolyte decomposition on the surface.These findings provide useful information for further optimizing the capacity and the stability of graphite anode in DIBs.展开更多
Objective:To evaluate incidence of interscalar excursions between round window (RW) and cochleostomy approaches for cochlear implant (CI) insertion. Methods:This was a retrospective case-comparison. Flat-panel CT (FPC...Objective:To evaluate incidence of interscalar excursions between round window (RW) and cochleostomy approaches for cochlear implant (CI) insertion. Methods:This was a retrospective case-comparison. Flat-panel CT (FPCT) scans for 8 CI users with Med-El standard length electrode arrays were collected. Surgical technique was identified by a combination of operative notes and FPCT imaging. Four cochleae underwent round win-dow insertion and 4 cochleae underwent cochleostomy approaches anterior and inferior to the round window. Results:In our pilot study, cochleostomy approaches were associated with a higher likeli-hood of interscalar excursion. Within the cochleostomy group, we found 29% of electrode contacts (14 of 48 electrodes) to be outside the scala tympani. On the other hand, 8.5%of the electrode contacts (4 of 47 electrodes) in the round window insertion group were extra-scalar to the scala tympani. These displacements occurred at a mean angle of occur-rence of 364°±133°, near the apex of the cochlea. Round window electrode displacements tend to localize at angle of occurrences of 400? or greater. Cochleostomy electrodes occurred at an angle of occurrence of 19°e490°.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51222210 and 11234013)the One Hundred Talent Project of the Chinese Academy of Sciences
文摘In order to achieve better Na storage performance, most layered oxide positive electrode materials contain toxic and expensive transition metals Ni and/or Co, which are also widely used for lithium-ion batteries. Here we report a new quaternary layered oxide consisting of Cu, Fe, Mn, and Ti transition metals with O3-type oxygen stacking as a positive electrode for room-temperature sodium-ion batteries. The material can be simply prepared by a high-temperature solidstate reaction route and delivers a reversible capacity of 94 m Ah/g with an average storage voltage of 3.2 V. This paves the way for cheaper and non-toxic batteries with high Na storage performance.
基金supported by the National Natural Science foundation of China(No.50081004,50271032)the Special Fund for Major State Basic Research of China(973 Project 2002 CB 211800)Nankai-Tianjin University Union Science Fund.
文摘Magnesium-based rechargeable batteries might be an interesting future alternative to lithium-based batteries. It is so far well known that Mg2+ ion insertion into ion-transfer hosts proceeds slowly compared with Li+, so it is necessary to realize fast Mg2+ transport in the host in addition to other requirements as practical cathode materials for magnesium batteries. Positive electrode materials based on inorganic transition-metal oxides, sulfides, and borides are the only ones used up to now to insert magnesium ions. In this paper, the available results of research on materials suitable as possible, for secondary magnesium batteries, are reviewed.
基金financial support of the National Natural Science Foundation of China (project no. 51504231, 51504232, 51774262 and 21325628)Open Project of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization (project no. CNMRCUKF1704)
文摘In the present paper, multi-walled carbon nanotubes（MWCNTs） are successfully assembled on graphite felt（GF） using sucrose pyrolysis method for the first time. The in situ formed pyrolytic carbon is chosen as the binder because it is essentially carbon materials as well as CNTs and GF which has a natural tendency to achieve high bonding strength and low contact resistance. The MWCNTs/GF electrode is demonstrated to increase surface area, reduce polarization, lower charge transfer resistance and improve energy conversion efficiency comparing with GF. This excellent electrochemical performance is mainly ascribed to the high electro-catalytic activity of MWCNTs and increasing surface area.
文摘The reactivity between charged Li(Li_(0.115)Mn_(0.529)Ni_(0.339)Al_(0.017))O_(2)(Li-rich),single crystal Li(Ni_(0.8)Mn_(0.1)Co_(0.1))O_(2)(SC-NMC811),LiFePO_(4)(LFP) and LiMn_(0.8)Fe_(0.2)PO_(4)(LMFP) positive electrodes at different states of charge(SOCs) and traditional carbonate-based electrolyte at elevated temperatures is systematically studied using accelerating rate calorimetry(ARC).The results show that the SOC greatly affects the thermal stability of the Li-rich and SC-NMC811 when traditional carbonate-based electrolyte is used.Although an increase in the SOC increases the energy density of lithium-ion cells,it also increases the reactivity between charged Li-rich and SC-NMC811 samples with electrolyte at elevated temperatures.In comparison with SC-NMC811,the Li-rich samples are much more stable at elevated temperatures,and the latter have higher specific capacity.SC-NMC811 samples are less reactive than traditional polycrystalline NMC811.Both LFP and LMFP samples show excellent thermal stability at elevated temperatures.The substitution of Fe by Mn in the olivine series positive materials does not impact the reactivity with electrolyte.
基金Financial support from the National Key R&D Program of China(No.2018YFB0104400)the National Natural Science Foundation of China(Nos.51725401,51874019 and 11672341)the Fundamental Research Funds for the Central Universities(No.FRFTP-17-002C2)is gratefully acknowledged.
文摘To achieve stable positive electrode for promoting the overall electrochemical performance of Al batteries(ABs),here novel cobalt boride(CoB)nanoclusters are synthesized to construct composite electrodes with few-layer graphene(FLG).Due to the presence of amorphous channels in the employed CoB nanoclusters,the ABs with FLG/CoB composite positive electrodes exhibit high rate.capability and both mechanical and electrochemical stability in the ABs.With assistance of in situ scanning electron microscopy(SEM),the observation results suggest that the positive electrode of CoB nanoclusters holds almost ignorable volume variation upon electrochemical processes,which substantially alleviates the massive electrode expansion induced by the anion intercalation in the composite positive electrode.Interestingly,the composite positive electrodes provide stable reversible energy storage capability within a broadened temperature range(-30-60℃),promising a novel strategy to design advanced ABs positive electrodes with enhanced overall energy storage performance.
文摘In a steady-state plasma,the loss rate of plasma particles to the chamber wall and surfaces in contact with plasma is balanced by the ionization rate of background neutrals in the hot-filament discharges.The balance between the loss rate and ionization rate of plasma particles(electrons and ions)maintains quasi-neutrality of the bulk plasma.In the presence of an external perturbation,it tries to retain its quasi-neutrality condition.In this work,we studied how the properties of bulk plasma are affected by an external DC potential perturbation.An auxiliary biased metal disk electrode was used to introduce a potential perturbation to the plasma medium.A single Langmuir probe and an emissive probe,placed in the line of the discharge axis,were used for the characterization of the bulk plasma.It is observed that only positive bias to the auxiliary metal disk increases the plasma potential,electron temperature,and plasma density but these plasma parameters remain unaltered when the disk is biased with a negative potential with respect to plasma potential.The observed plasma parameters for two different-sized,positively as well as negatively biased,metal disks are compared and found inconsistent with the existing theoretical model at large positive bias voltages.The role of the primary energetic electrons population in determining the plasma parameters is discussed.The experimentally observed results are qualitatively explained on the basis of electrostatic confinement arising due to the loss of electrons to a biased metal disk electrode.
基金supported by the National Natural Science Foundation of China(No.51725401 and 51874019)the Fundamental Research Funds for the Central Universities(FRF-TP-17-002C2)。
文摘Aluminum batteries are attractive in electrochemical energy storage due to high energy density and lowcost aluminum,while the energy density is limited for the lack of favorable positive electrode materials to match aluminum negative electrodes.Tellurium positive electrode is intrinsically electrically conductive among chalcogen and holds high theoretical specific capacity(1260.27 mAh g^(-1)) and discharge voltage plateau(~1,5 V).However,the chemical and electrochemical dissolution of Te active materials results in the low material utilization and poor cycling stability.To enhance the electrochemical performance,herein a nitrogen doped porous carbon(N-PC) is derived from zeolite imidazolate framework(ZIF-67)as an effective tellurium host to suppress the undesired shuttle effect.In order to inhibit the volume expansion of N-PC during the charge/discharge process,the reduced graphene oxide(rGO) nanosheets are introduced to form a stable host materials(N-PC-rGO) for stabilizing Te.The physical encapsulation and chemical confinement to soluble tellurium species are achieved.N-PC-rGO-Te positive electrode exhibits an improved initial specific capacity and long-term cycling performance at a current density of 500 mA g^(-1)(initial specific capacity:935.5 mAh g^(-1);after 150 cycles:467.5 mAh g^(-1)), highlighting a promising design strategy for inhibiting chemical and electrochemical dissolution of Te.
文摘The effect of operating conditions on the aluminium content of Ni-Al alloy deposit and the catalytic function of NaF on electrodeposition in the nonaqueous solution containing aluminium are investigated.The results indicate that the plated aluminuim content will be increased with the rise of current density in a given range.When the current density is 2.5A/dm 2,nickle aluminium alloy containing 13.1 wt% aluminium will be deposited.The plated aluminium content will be increased by 2wt% as 0.1mol/L NaF is added to the bath.
基金support from the National Natural Science Foundation of China(Grant No.U22A20145,51904115,52072151,52171211,52102253,and 52271218)Jinan Independent Innovative Team(2020GXRC015)Major Program of Shandong Province Natural Science Foundation(ZR2023ZD43,ZR2021ZD05).
文摘Low specific capacitances and/or limited working potential(≤4.5 V).of the prevalent carbon-based positive electrodes as the inborn bottleneck seriously hinder practical advancement of lithium-ion capacitors.Thus,breakthroughs in enhancement of both specific capacitances and upper cutoff potentials are enormously significant for high-energy density lithium-ion capacitors.Herein,we first meticulously design and scalably fabricate a commercializable fluorine-doped porous carbon material with competitive tap density,large active surface,appropriate aperture distribution,and promoted affinity with the electrolyte,rendering its abundant electroactive inter-/surface and rapid PF_(6)^(-)transport.Theoretical calculations authenticate that fluorine-doped porous carbon possesses lower PF_(6)^(-)adsorption energy and stronger interaction with PF_(6)^(-).Thanks to the remarkable structural/compositional superiority,when served as a positive electrode toward lithium-ion capacitors,the commercial-level fluorine-doped porous carbon showcases the record-breaking electrochemical properties within a wider working window of 2.5-5.0 V(vs Li/Li^(+))in terms of high-rate specific capacitances and long-duration stability,much superior to commercial activated carbon.More significantly,the 4.5 V-class graphite//fluorine-doped porous carbon lithium-ion capacitors are first constructed and manifest competitive electrochemical behaviors with long-cycle life,modest polarization,and large energy density.Our work provides a commendable positive paradigm and contributes a major step forward in next-generation lithium-ion capacitors and even other high-energy density metal-ion capacitors.
文摘The Ni-rich Li[Ni0.6Co0.2Mn0.2]O2 surface has been modified with H3PO4. After coating at 80 ℃, the products were heated further at a moderate temperature of 500 ℃ in air, when the added H3PO4 transformed to Li3PO4 after reacting with residual LiOH and Li2CO3 on the surface. A thin and uniform smooth nanolayer （〈 10 nm） was observed on the surface of Li[Ni0.6Co0.2Mn0.2]O2 as confirmed by transmission electron microscopy （TEM）. Time-of-flight secondary ion mass spectroscopic （ToF-SIMS） data exhibit the presence of LIP＋, LiPO-, and Li2PO2＋ fragments, indicating the formation of the Li3PO4 coating layer on the surface of the Li[Ni0.6Co0.2Mn0.2]O2. As a result, the amounts of residual lithium compounds, such as LiOH and Li2CO3, are significantly reduced. As a consequence, the LigPO4-coated Li[Ni0.6Co0.2Mn0.2]O2 exhibits noticeable improvement in capacity retention and rate capability due to the reduction of residual LiOH and Li2CO3. Further investigation of the extensively cycled electrodes by X-ray diffraction （XRD）, TEM, and ToF-SIMS demonstrated that the LiBPO4 coating layers have multi-functions： Absorption of water in the electrolyte that lowers the HF level, HF scavenging, and protection of the active materials from deleterious side reactions with the electrolyte during extensive cycling, enabling high capacity retention over 1,000 cycles.
基金This research was financially supported by Soft Science Research Project of Guangdong Province(No.2017B030301013)the Shenzhen Science and Technology Research(Nos.CYJ20170818085823773 and ZDSYS201707281026184).
文摘Graphite as a positive electrode material of dual ion batteries(DIBs)has attracted tremendous attentions for its advantages including low lost,high working voltage and high energy density.However,very few literatures regarding to the real-time observation of anion intercalation behavior and surface evolution of graphite in DIBs have been reported.Herein,we use in situ atomic force microscope(AFM)to directly observe the intercalation/de-intercalation processes of PF6^-in graphite in real time.First,by measuring the change in the distance between graphene layers during intercalation,we found that PF6^-intercalates in one of every three graphite layers and the intercalation speed is measured to be 2μm-min^-1.Second,graphite will wrinke and suffer structural damnages at high voltages,along with severe electrolyte decomposition on the surface.These findings provide useful information for further optimizing the capacity and the stability of graphite anode in DIBs.
文摘Objective:To evaluate incidence of interscalar excursions between round window (RW) and cochleostomy approaches for cochlear implant (CI) insertion. Methods:This was a retrospective case-comparison. Flat-panel CT (FPCT) scans for 8 CI users with Med-El standard length electrode arrays were collected. Surgical technique was identified by a combination of operative notes and FPCT imaging. Four cochleae underwent round win-dow insertion and 4 cochleae underwent cochleostomy approaches anterior and inferior to the round window. Results:In our pilot study, cochleostomy approaches were associated with a higher likeli-hood of interscalar excursion. Within the cochleostomy group, we found 29% of electrode contacts (14 of 48 electrodes) to be outside the scala tympani. On the other hand, 8.5%of the electrode contacts (4 of 47 electrodes) in the round window insertion group were extra-scalar to the scala tympani. These displacements occurred at a mean angle of occur-rence of 364°±133°, near the apex of the cochlea. Round window electrode displacements tend to localize at angle of occurrences of 400? or greater. Cochleostomy electrodes occurred at an angle of occurrence of 19°e490°.
