As promising,low-cost alternatives of lithiumion batteries for large-scale electric energy storage,sodiumion batteries(SIBs)have been studied by many researchers.However,the relatively large size of Na+leads to sluggi...As promising,low-cost alternatives of lithiumion batteries for large-scale electric energy storage,sodiumion batteries(SIBs)have been studied by many researchers.However,the relatively large size of Na+leads to sluggish diffusion kinetics and poor cycling stability in most cathode materials,restricting their further applications.In this work,we demonstrated a novel K+-intercalated Mn/Ni-based layered oxide material(K0.7Mn0.7Ni0.3O2,denoted as KMNO)with stabilized and enlarged diffusion channels for high energy density SIBs.A spontaneous ion exchange behavior in forming K0.1Na0.7Mn0.7Ni0.3O2between the KMNO electrode and the sodium ion electrolyte was clearly revealed by in situ X-ray diffraction and ex situ inductively coupled plasma analysis.The interlayer space varied from 6.90 to 5.76?,larger than that of Na0.7Mn0.7Ni0.3O2(5.63?).The enlarged ionic diffusion channels can effectively increase the ionic diffusion coefficient and simultaneously provide more K+storage sites in the product framework.As a proof-of-concept application,the SIBs with the as-prepared KMNO as a cathode display a high reversible discharge capacity(161.8 mA h g-1at0.1 A g-1),high energy density(459 W h kg-1)and superior rate capability of 71.1 mA h g-1at 5 A g-1.Our work demonstrates that the K+pre-intercalation strategy endows the layered metal oxides with excellent sodium storage performance,which provides new directions for the design of cathode materials for various batteries.展开更多
Layered F-doped cathode materials 0.3 Li_2 MnO_3-0.7 LiMn_(1/3)Ni_(1/3)CO_(1/3))O_(2-x)F_x(x = 0, 0.01, 0.02, 0.03, 0.04,0.05) microspheres made up of nanosized primary grains were prepared through co-precipitation me...Layered F-doped cathode materials 0.3 Li_2 MnO_3-0.7 LiMn_(1/3)Ni_(1/3)CO_(1/3))O_(2-x)F_x(x = 0, 0.01, 0.02, 0.03, 0.04,0.05) microspheres made up of nanosized primary grains were prepared through co-precipitation method. The sample of x = 0.02 demonstrates a large discharge capacity of226 mAh g^(-1) over 100 cycles at 0.1 C and excellent rate performance with discharge capacity of 96 mAh g-1 at 5.0 C and room temperature. Particularly, this material shows much enhanced electrochemical performances even at high temperature of 55 ℃. It delivers a quite high discharge capacity of 233.7 mAh·g^(-1) at 1.0 C with capacity retention as high as 97.9% after 100 cycles. The results demonstrate that the fluorine incorporation stabilizes the cathode structure and maintains stable interfacial resistances.展开更多
Since lithium-ion battery with high energy density is the key component for next-generation electrical vehicles, a full understanding of its thermal behaviors at different discharge rates is quite important for the de...Since lithium-ion battery with high energy density is the key component for next-generation electrical vehicles, a full understanding of its thermal behaviors at different discharge rates is quite important for the design and thermal management of lithium-ion batteries （LIBs） pack/module. In this work, a 25 Ah pouch type Li[Ni0.7 Co0.15Mn0.15]O2/graphite LIBs with specific energy of 200 Wh.kg-1 were designed to investigate their thermal behaviors, including temperature distribution, heat generation rate, heat capacity and heat transfer coefficient with environment. Results show that the temperature increment of the charged pouch batteries strongly depends on the discharge rate and depth of discharge. The heat generation rate is mainly influenced by the irreversible heat effect, while the reversible heat is important at all discharge rates and contributes much to the middle evolution of the tem- perature during discharge, especially at low rate. Subse- quently, a prediction model with lumped parameters was used to estimate the temperature evolution at different discharge rates of LIBs. The predicted results match well with the experimental results at all discharge rates. Therefore, the thermal model is suitable to predict the average temperature for the large-scale batteries under normal operating conditions.展开更多
The synthesis process of LiCo0.3Ni0.7O2 was investigated by FT-IR, mass spectroscopy, elemental analysis SEM, BET, TG/DTA and XRD in this paper. The results re- vealed that lithium and transition metal ions were trapp...The synthesis process of LiCo0.3Ni0.7O2 was investigated by FT-IR, mass spectroscopy, elemental analysis SEM, BET, TG/DTA and XRD in this paper. The results re- vealed that lithium and transition metal ions were trapped homogeneously on an atomic scale throughout the precursor Li2CO3, NiO and CoO are the intermediate products ob- tained after decomposition of the precursor and Li2CO3 un- dergoes direct reactions with NiO and CoO to form LiCo0.3Ni0.7O2. Moreover, the kinetics of formation of LiCo0.3Ni0.7O2 by citrate sol-gel method is faster than the case of the conventional solid-state reaction between lithium car- bonate and corresponding reactants. The single phase of LiCo0.3Ni0.7O2 was synthesized at temperature as low as 550℃. The discharge capacity of LiCo0.3Ni0.7O2 increases from 127 to 185 mAh/g as the calcination temperature in- creasing from 550 to 750℃. After 100 cycles, the discharge capacity of the sample calcined at 750℃ is 155 mAh/g. The electrochemical study shows that the LiCo0.3Ni0.7O2 has high discharge capacity and good cycling behavior for lithium ion batteries.展开更多
基金supported by the National Natural Science Foundation of China(51872218 and 51832004)the National Key R&D Program of China(2016YFA0202603)the Fundamental Research Funds for the Central Universities(WUT:2017III009)。
文摘As promising,low-cost alternatives of lithiumion batteries for large-scale electric energy storage,sodiumion batteries(SIBs)have been studied by many researchers.However,the relatively large size of Na+leads to sluggish diffusion kinetics and poor cycling stability in most cathode materials,restricting their further applications.In this work,we demonstrated a novel K+-intercalated Mn/Ni-based layered oxide material(K0.7Mn0.7Ni0.3O2,denoted as KMNO)with stabilized and enlarged diffusion channels for high energy density SIBs.A spontaneous ion exchange behavior in forming K0.1Na0.7Mn0.7Ni0.3O2between the KMNO electrode and the sodium ion electrolyte was clearly revealed by in situ X-ray diffraction and ex situ inductively coupled plasma analysis.The interlayer space varied from 6.90 to 5.76?,larger than that of Na0.7Mn0.7Ni0.3O2(5.63?).The enlarged ionic diffusion channels can effectively increase the ionic diffusion coefficient and simultaneously provide more K+storage sites in the product framework.As a proof-of-concept application,the SIBs with the as-prepared KMNO as a cathode display a high reversible discharge capacity(161.8 mA h g-1at0.1 A g-1),high energy density(459 W h kg-1)and superior rate capability of 71.1 mA h g-1at 5 A g-1.Our work demonstrates that the K+pre-intercalation strategy endows the layered metal oxides with excellent sodium storage performance,which provides new directions for the design of cathode materials for various batteries.
基金financially supported by the National Natural Science Foundation of China (No. 51372136)the NSFC-Guangdong United Fund (No. U1401246)
文摘Layered F-doped cathode materials 0.3 Li_2 MnO_3-0.7 LiMn_(1/3)Ni_(1/3)CO_(1/3))O_(2-x)F_x(x = 0, 0.01, 0.02, 0.03, 0.04,0.05) microspheres made up of nanosized primary grains were prepared through co-precipitation method. The sample of x = 0.02 demonstrates a large discharge capacity of226 mAh g^(-1) over 100 cycles at 0.1 C and excellent rate performance with discharge capacity of 96 mAh g-1 at 5.0 C and room temperature. Particularly, this material shows much enhanced electrochemical performances even at high temperature of 55 ℃. It delivers a quite high discharge capacity of 233.7 mAh·g^(-1) at 1.0 C with capacity retention as high as 97.9% after 100 cycles. The results demonstrate that the fluorine incorporation stabilizes the cathode structure and maintains stable interfacial resistances.
基金financially supported by the Program from Ministry of Science and Technology of China(No.2011AA11A254)the National High Technology Research and Development Program of China(No.2012AA110102)
文摘Since lithium-ion battery with high energy density is the key component for next-generation electrical vehicles, a full understanding of its thermal behaviors at different discharge rates is quite important for the design and thermal management of lithium-ion batteries （LIBs） pack/module. In this work, a 25 Ah pouch type Li[Ni0.7 Co0.15Mn0.15]O2/graphite LIBs with specific energy of 200 Wh.kg-1 were designed to investigate their thermal behaviors, including temperature distribution, heat generation rate, heat capacity and heat transfer coefficient with environment. Results show that the temperature increment of the charged pouch batteries strongly depends on the discharge rate and depth of discharge. The heat generation rate is mainly influenced by the irreversible heat effect, while the reversible heat is important at all discharge rates and contributes much to the middle evolution of the tem- perature during discharge, especially at low rate. Subse- quently, a prediction model with lumped parameters was used to estimate the temperature evolution at different discharge rates of LIBs. The predicted results match well with the experimental results at all discharge rates. Therefore, the thermal model is suitable to predict the average temperature for the large-scale batteries under normal operating conditions.
基金the EH.D Foundation of China(Grant No.20020610027)
文摘The synthesis process of LiCo0.3Ni0.7O2 was investigated by FT-IR, mass spectroscopy, elemental analysis SEM, BET, TG/DTA and XRD in this paper. The results re- vealed that lithium and transition metal ions were trapped homogeneously on an atomic scale throughout the precursor Li2CO3, NiO and CoO are the intermediate products ob- tained after decomposition of the precursor and Li2CO3 un- dergoes direct reactions with NiO and CoO to form LiCo0.3Ni0.7O2. Moreover, the kinetics of formation of LiCo0.3Ni0.7O2 by citrate sol-gel method is faster than the case of the conventional solid-state reaction between lithium car- bonate and corresponding reactants. The single phase of LiCo0.3Ni0.7O2 was synthesized at temperature as low as 550℃. The discharge capacity of LiCo0.3Ni0.7O2 increases from 127 to 185 mAh/g as the calcination temperature in- creasing from 550 to 750℃. After 100 cycles, the discharge capacity of the sample calcined at 750℃ is 155 mAh/g. The electrochemical study shows that the LiCo0.3Ni0.7O2 has high discharge capacity and good cycling behavior for lithium ion batteries.
