Al-doped manganese dioxide(MnO_(2))was synthesized by simple hydrothermal method,and a controllable phase transition of the MnO_(2)crystal phase fromβtoδwas achieved.The effects of Al doping concentration on the str...Al-doped manganese dioxide(MnO_(2))was synthesized by simple hydrothermal method,and a controllable phase transition of the MnO_(2)crystal phase fromβtoδwas achieved.The effects of Al doping concentration on the structure and electrochemical properties of electrode materials were studied in detail.The results show that the controlled synthesis requires a synergy between KMnO_(4),MnCl_(2)and AlCl_(3),and that Al^(3+)plays an important role.Compared with the pure phase MnO_(2),the crystallinity of Al-doped MnO_(2)decreases and the specific surface area increases,which provides more active sites for the electrode material.When 3 mmol Al^(3+)is added,the prepared MnO_(2)-3 has the largest specific capacitance and the highest rate performance.The energy density of the asymmetric supercapacitor(ASC)with MnO_(2)-3 as the positive electrode and activated carbon(AC)as the negative electrode can reach 18.4 W·h/kg at the power density of 400 W/kg,and the capacity can maintain 90%of the initial value after 20000 cycles,indicating that Al-doped MnO_(2)has certain practical application value.This study provides favorable guidance for MnO_(2)as a high performance electrode material.展开更多
Lithium-sulfur batteries are considered as one of the potential solutions as integrating renewable energy systems for large-scale energy storage because of their high theoretical energy density(2600 Wh·kg^(-1))an...Lithium-sulfur batteries are considered as one of the potential solutions as integrating renewable energy systems for large-scale energy storage because of their high theoretical energy density(2600 Wh·kg^(-1))and specific capacity(1675 mAh·g^(-1)).Currently,various strategies have been proposed to overcome the technical barriers,e.g.,“shuttle effect”,capacity decay and volumetric change,which impede the successful commercialization of lithium-sulfur batteries.This paper reviews the applications of metal nitrides as the cathode hosts for high-performance lithium-sulfur batteries,summa-rizes the design strategies of different host materials,and discusses the relationship between the properties of metal nitrides and their electrochemical performances.Finally,reasonable suggestions for the design and development of metal nitrides,along with ideas to promote future breakthroughs,are proposed.We hope that this review could attract more attention to metal nitrides and their derivatives,and further promote the electrochemical performance of lithium-sulfur batteries.展开更多
基金Project(202203021221138)supported by the Collaborative Innovation Center for Shanxi Advanced Permanent Materials and Technologythe 1331 Engineering of Shanxi ProvinceFundamental Research Program of Shanxi Province,China。
文摘Al-doped manganese dioxide(MnO_(2))was synthesized by simple hydrothermal method,and a controllable phase transition of the MnO_(2)crystal phase fromβtoδwas achieved.The effects of Al doping concentration on the structure and electrochemical properties of electrode materials were studied in detail.The results show that the controlled synthesis requires a synergy between KMnO_(4),MnCl_(2)and AlCl_(3),and that Al^(3+)plays an important role.Compared with the pure phase MnO_(2),the crystallinity of Al-doped MnO_(2)decreases and the specific surface area increases,which provides more active sites for the electrode material.When 3 mmol Al^(3+)is added,the prepared MnO_(2)-3 has the largest specific capacitance and the highest rate performance.The energy density of the asymmetric supercapacitor(ASC)with MnO_(2)-3 as the positive electrode and activated carbon(AC)as the negative electrode can reach 18.4 W·h/kg at the power density of 400 W/kg,and the capacity can maintain 90%of the initial value after 20000 cycles,indicating that Al-doped MnO_(2)has certain practical application value.This study provides favorable guidance for MnO_(2)as a high performance electrode material.
文摘Lithium-sulfur batteries are considered as one of the potential solutions as integrating renewable energy systems for large-scale energy storage because of their high theoretical energy density(2600 Wh·kg^(-1))and specific capacity(1675 mAh·g^(-1)).Currently,various strategies have been proposed to overcome the technical barriers,e.g.,“shuttle effect”,capacity decay and volumetric change,which impede the successful commercialization of lithium-sulfur batteries.This paper reviews the applications of metal nitrides as the cathode hosts for high-performance lithium-sulfur batteries,summa-rizes the design strategies of different host materials,and discusses the relationship between the properties of metal nitrides and their electrochemical performances.Finally,reasonable suggestions for the design and development of metal nitrides,along with ideas to promote future breakthroughs,are proposed.We hope that this review could attract more attention to metal nitrides and their derivatives,and further promote the electrochemical performance of lithium-sulfur batteries.
