Due to the low cost,high working voltage and high storage capacity,Li-rich Mn-based layered compounds show promise as the cathode materials for lithiumion batteries(LIBs).However,the side reactions at the solid-liquid...Due to the low cost,high working voltage and high storage capacity,Li-rich Mn-based layered compounds show promise as the cathode materials for lithiumion batteries(LIBs).However,the side reactions at the solid-liquid interface of the cathode will lead to rapid capacity decay and inferior rate performance.Herein,this article proposes a liquid-phase dispersion strategy to introduce a Na_(2)WO_(4)layer on the Li_(1.2)Ni_(0.13)-Co_(0.13)Mn_(0.54)O_(2) cathode,which can reduce the side effects between raw materials and electrolyte and promote the insertion/extraction rate of Li^(+),thus enhancing the material stability and rate performance.As a result,the capacity retention rate is 96.9%after 200 cycles under 2C.Moreover,the capacities are 177.5,149.5,111.1 and58.3 mAh·g^(-1)at 1C,2C,5C and 10C,implying a superior fast charging performance.The exceptional performance can be ascribed to both the increased conductivity and enhanced structural stability of the cathode material.What's more,based on the investigation of ion insertion/extraction behavior in electrode materials and the ion migration kinetics in the electrolyte,this study suggests that coating Li-rich Mn-based materials with Na_(2)WO_(4)can be a promising strategy to improve their performance in LIBs.展开更多
Na_(2)Li_(2)Ti_(6)O_(14) as a reliable anode material is becoming a hopeful candidate for Li-ion battery.Nevertheless,the pristine Na_(2)Li_(2)Ti_(6)O_(14) usually suffer from bad rate performance and poor cycling sta...Na_(2)Li_(2)Ti_(6)O_(14) as a reliable anode material is becoming a hopeful candidate for Li-ion battery.Nevertheless,the pristine Na_(2)Li_(2)Ti_(6)O_(14) usually suffer from bad rate performance and poor cycling stability under high current due to limited diffusion kinetics and poor electrical conductivity.Here,the PPy-coated Na_(2)Li_(2)Ti_(6)O_(14) composites are successfully obtained via the solid-state method and followed by chemical oxidation process in the first time.The results of tests prove that the Na_(2)Li_(2)Ti_(6)O_(14)@PPy composites have better electrochemical performance than the bare Na_(2)Li_(2)Ti_(6)O_(14) because of the excellent electrical conductivity and the special macromolecular architecture of PPy.In particular,the Na_(2) Li_(2) Ti_(6) O_(14) @PPy(4 wt%)exhibits excellent charge capacities of about 223.2,218.0,200.8,184.3 and 172.6 mAh g^(-1) at 50,100,200,300 and500 mA g^(-1),respectively,revealing the best rate capability of all electrode materials.The Na_(2)Li_(2)Ti_(6)O_(14)@PPy(4 wt%)not only has the highest charge capacity under 0.5 mA g^(-1),but also has the highest capacity retention of 85.12%among all samples after 100 loops.Hence,the PPy coating is known as a promising way to improve the electrochemical property of Na_(2)Li_(2)Ti_(6)O_(14).The PPy-coated Na_(2)Li_(2)Ti_(6)O_(14) demonstrates the great prospect as promising negative materials for Li-ion batteries.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52374301)the Natural Science Foundation of Hebei Province(No.E2022501014)+2 种基金the Science and Technology Research Youth Fund Project of Higher Education Institutions of Hebei Province(No.QN2022196)the Fundamental Research Funds for the Central Universities(No.N2123001)the Natural Science Foundation of Hebei Province of China(No.B2020501003)。
文摘Due to the low cost,high working voltage and high storage capacity,Li-rich Mn-based layered compounds show promise as the cathode materials for lithiumion batteries(LIBs).However,the side reactions at the solid-liquid interface of the cathode will lead to rapid capacity decay and inferior rate performance.Herein,this article proposes a liquid-phase dispersion strategy to introduce a Na_(2)WO_(4)layer on the Li_(1.2)Ni_(0.13)-Co_(0.13)Mn_(0.54)O_(2) cathode,which can reduce the side effects between raw materials and electrolyte and promote the insertion/extraction rate of Li^(+),thus enhancing the material stability and rate performance.As a result,the capacity retention rate is 96.9%after 200 cycles under 2C.Moreover,the capacities are 177.5,149.5,111.1 and58.3 mAh·g^(-1)at 1C,2C,5C and 10C,implying a superior fast charging performance.The exceptional performance can be ascribed to both the increased conductivity and enhanced structural stability of the cathode material.What's more,based on the investigation of ion insertion/extraction behavior in electrode materials and the ion migration kinetics in the electrolyte,this study suggests that coating Li-rich Mn-based materials with Na_(2)WO_(4)can be a promising strategy to improve their performance in LIBs.
基金financially supported by the National Natural Science Foundation of China(No.U1960107)the“333”Talent Project of Hebei Province(No.A202005018)the Fundamental Research Funds for the Central Universities(No.N2123001)。
文摘Na_(2)Li_(2)Ti_(6)O_(14) as a reliable anode material is becoming a hopeful candidate for Li-ion battery.Nevertheless,the pristine Na_(2)Li_(2)Ti_(6)O_(14) usually suffer from bad rate performance and poor cycling stability under high current due to limited diffusion kinetics and poor electrical conductivity.Here,the PPy-coated Na_(2)Li_(2)Ti_(6)O_(14) composites are successfully obtained via the solid-state method and followed by chemical oxidation process in the first time.The results of tests prove that the Na_(2)Li_(2)Ti_(6)O_(14)@PPy composites have better electrochemical performance than the bare Na_(2)Li_(2)Ti_(6)O_(14) because of the excellent electrical conductivity and the special macromolecular architecture of PPy.In particular,the Na_(2) Li_(2) Ti_(6) O_(14) @PPy(4 wt%)exhibits excellent charge capacities of about 223.2,218.0,200.8,184.3 and 172.6 mAh g^(-1) at 50,100,200,300 and500 mA g^(-1),respectively,revealing the best rate capability of all electrode materials.The Na_(2)Li_(2)Ti_(6)O_(14)@PPy(4 wt%)not only has the highest charge capacity under 0.5 mA g^(-1),but also has the highest capacity retention of 85.12%among all samples after 100 loops.Hence,the PPy coating is known as a promising way to improve the electrochemical property of Na_(2)Li_(2)Ti_(6)O_(14).The PPy-coated Na_(2)Li_(2)Ti_(6)O_(14) demonstrates the great prospect as promising negative materials for Li-ion batteries.
