The interface instability between layered oxide cathode and sulfide electrolyte is a key point affecting the perform ance of sulfide-based all-solid-state lithium batteries.Coating with fast-ionic conductor and constr...The interface instability between layered oxide cathode and sulfide electrolyte is a key point affecting the perform ance of sulfide-based all-solid-state lithium batteries.Coating with fast-ionic conductor and constructing core-shell structure can effectively alleviate the interfacial side reactions and improve the interfacial stability between layered oxide and sulfide electrolyte.However,what have been neglected is the surface base(including Li_(2)CO_(3) and LiOH)of layered oxide can also affect the interfacial stability.To clarify this point clearly and improve the interfacial stability,the surface base of LiCoO_(2)(LCO)is regulated and investigated in this work.First,LCO with surface base Li_(2)CO_(3)(LCO@Li_(2)CO_(3))is prepared by the reaction of Co_(3)O_4 and excess Li_(2)CO_(3).Then,the bare LCO is obtained after LCO@Li_(2)CO_(3) is washed with deionized water and calcined again.Besides,LCO with surface base Li_(2)O(LCO@Li_(2)O)is also prepared with the bare LCO and LiOH.As a result,the electrochemical performances of LCO@Li_(2)O are significantly improved and much higher than those of LCO@Li_(2)CO_(3) and the bare LCO electrodes.In particular,LCO@Li_(2)O-2 cathode display the most outstanding electrochemical performances(discharge capacity138.4 mAh·g^(-1)at 0.2C,105 mAh·g^(-1)at 2C and a capacity retention of 95.4%after 150 cycles at 0.5C).The high discharge capacity and excellent cycle stability of LCO@Li_(2)O electrode confirm the effectiveness of regulating the surface base of layered oxide from Li_(2)CO_(3) to Li_(2)O.The surface base regulating is expected to be a simple but effective strategy to construct the stable interface between the cathode and the sulfide electrolyte of the all-solid-state lithium batteries.展开更多
Li Ni0.5Mn0.5O2 as a cathode material for Li-ion battery was prepared by the metal acetate decomposition method, sol–gel method, and carbonate co-precipitation method, respectively. The influences of synthesis method...Li Ni0.5Mn0.5O2 as a cathode material for Li-ion battery was prepared by the metal acetate decomposition method, sol–gel method, and carbonate co-precipitation method, respectively. The influences of synthesis methods on the physical and electrochemical behaviors of Li Ni0.5Mn0.5O2 were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and electrochemical tests. XRD patterns show that both the sol–gel and carbonate co-precipitation methods can form single phase of layered structure, while a trace of Ni O impurity is observed via the metal acetate decomposition method. SEM results show the as-prepared carbonate particle has a spherical morphology with an average diameter of 10 lm, consisted of primary nano-sized particles with particle diameter of200 nm. The sample prepared by the carbonate co-precipitation method exhibits the highest discharge specific capacity and the best cycling stability, which results from the steady homogeneity of precursor constant by the fixation of CO2-3group. It can deliver an initial discharge specific capacity of 186.3 m Ahág-1, and retain 170 m Ahág-1after100 cycles at a current rate of 20 m Aág-1in the voltage range of 2.5–4.7 V at 25 °C. Moreover, even at the high temperature of 55 °C, it still delivers a reversible specific capacity of 222.6 m Ahág-1with little capacity loss after 30 cycles.展开更多
基金financially supported by the National Key Research and Development Program of China (No.2018YFE0111600)the National Natural Science Foundation of China (Nos.52172224 and 22279090)the Science and Technology Major Project of China National Machinery Industry Corporation (No.SINOMAST-ZDZX-2019-04)。
文摘The interface instability between layered oxide cathode and sulfide electrolyte is a key point affecting the perform ance of sulfide-based all-solid-state lithium batteries.Coating with fast-ionic conductor and constructing core-shell structure can effectively alleviate the interfacial side reactions and improve the interfacial stability between layered oxide and sulfide electrolyte.However,what have been neglected is the surface base(including Li_(2)CO_(3) and LiOH)of layered oxide can also affect the interfacial stability.To clarify this point clearly and improve the interfacial stability,the surface base of LiCoO_(2)(LCO)is regulated and investigated in this work.First,LCO with surface base Li_(2)CO_(3)(LCO@Li_(2)CO_(3))is prepared by the reaction of Co_(3)O_4 and excess Li_(2)CO_(3).Then,the bare LCO is obtained after LCO@Li_(2)CO_(3) is washed with deionized water and calcined again.Besides,LCO with surface base Li_(2)O(LCO@Li_(2)O)is also prepared with the bare LCO and LiOH.As a result,the electrochemical performances of LCO@Li_(2)O are significantly improved and much higher than those of LCO@Li_(2)CO_(3) and the bare LCO electrodes.In particular,LCO@Li_(2)O-2 cathode display the most outstanding electrochemical performances(discharge capacity138.4 mAh·g^(-1)at 0.2C,105 mAh·g^(-1)at 2C and a capacity retention of 95.4%after 150 cycles at 0.5C).The high discharge capacity and excellent cycle stability of LCO@Li_(2)O electrode confirm the effectiveness of regulating the surface base of layered oxide from Li_(2)CO_(3) to Li_(2)O.The surface base regulating is expected to be a simple but effective strategy to construct the stable interface between the cathode and the sulfide electrolyte of the all-solid-state lithium batteries.
基金financially supported by the National High Technology Research and Development Program of China (No. 2011AA11A234)the National Natural Science Foundation of China (Nos. 51272175 and 20901058)the Program for New Century Excellent Talents in University of China (No. NCET10-0952)
文摘Li Ni0.5Mn0.5O2 as a cathode material for Li-ion battery was prepared by the metal acetate decomposition method, sol–gel method, and carbonate co-precipitation method, respectively. The influences of synthesis methods on the physical and electrochemical behaviors of Li Ni0.5Mn0.5O2 were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and electrochemical tests. XRD patterns show that both the sol–gel and carbonate co-precipitation methods can form single phase of layered structure, while a trace of Ni O impurity is observed via the metal acetate decomposition method. SEM results show the as-prepared carbonate particle has a spherical morphology with an average diameter of 10 lm, consisted of primary nano-sized particles with particle diameter of200 nm. The sample prepared by the carbonate co-precipitation method exhibits the highest discharge specific capacity and the best cycling stability, which results from the steady homogeneity of precursor constant by the fixation of CO2-3group. It can deliver an initial discharge specific capacity of 186.3 m Ahág-1, and retain 170 m Ahág-1after100 cycles at a current rate of 20 m Aág-1in the voltage range of 2.5–4.7 V at 25 °C. Moreover, even at the high temperature of 55 °C, it still delivers a reversible specific capacity of 222.6 m Ahág-1with little capacity loss after 30 cycles.
