2 H phase molybdenum disulfide(2 H-MoS_(2))possesses the two-dimensional layered structure and high theoretical capacity,presenting excellent lithiation-delithiation property.However,the violent capacity decay within ...2 H phase molybdenum disulfide(2 H-MoS_(2))possesses the two-dimensional layered structure and high theoretical capacity,presenting excellent lithiation-delithiation property.However,the violent capacity decay within dozens of cycles still remains a great challenge due to lacking of in-depth failure mechanism.Herein,a novel decay-recovery-decay failure phenomenon upon long-term cycles is reported for the first time,which originates from the slow size change of Mo nanoparticles(NPs).Decay stages are triggered by many irregular-shaped Mo NPs with the increasing size up to~15 nm,leading to prominent pseudocapacitance failure and capacity loss.Subsequent recovery stages are attributed to the pulverization of coarse Mo NPs through surface sulfurization and accompanying lithiation.To overcome the instability issue,proper modifiers should be introduced to restrain the spontaneous growth of Mo NPs,such as aluminum oxide(Al_(2)O_(3)).The strong Mo-Al_(2)O_(3)bond gradually"drags"Al_(2)O_(3)fragments into the active material as the cycle continuously proceeds,resulting in the efficient refinement and the reversible conversion between Mo and MoS_(2).Therefore,the enhanced cycling stability and the capacity retention are successfully achieved.It is expected to provide a new insight into the energy storage of transition metal chalcogenide anode materials in rechargeable batteries.展开更多
基金financially supported by Beijing Municipal Great Wall Scholar Training Plan Project(CIT&TCD20190307)Beijing Municipal Commission of Education(KZ202210005003)+2 种基金National Natural Science Foundation of China(51621003,U1607110,12074017)Beijing Hundred,Thousand and Ten Thousand Talent Project(2020016)Beijing municipal high-level innovative team building program(IDHT20190503)。
文摘2 H phase molybdenum disulfide(2 H-MoS_(2))possesses the two-dimensional layered structure and high theoretical capacity,presenting excellent lithiation-delithiation property.However,the violent capacity decay within dozens of cycles still remains a great challenge due to lacking of in-depth failure mechanism.Herein,a novel decay-recovery-decay failure phenomenon upon long-term cycles is reported for the first time,which originates from the slow size change of Mo nanoparticles(NPs).Decay stages are triggered by many irregular-shaped Mo NPs with the increasing size up to~15 nm,leading to prominent pseudocapacitance failure and capacity loss.Subsequent recovery stages are attributed to the pulverization of coarse Mo NPs through surface sulfurization and accompanying lithiation.To overcome the instability issue,proper modifiers should be introduced to restrain the spontaneous growth of Mo NPs,such as aluminum oxide(Al_(2)O_(3)).The strong Mo-Al_(2)O_(3)bond gradually"drags"Al_(2)O_(3)fragments into the active material as the cycle continuously proceeds,resulting in the efficient refinement and the reversible conversion between Mo and MoS_(2).Therefore,the enhanced cycling stability and the capacity retention are successfully achieved.It is expected to provide a new insight into the energy storage of transition metal chalcogenide anode materials in rechargeable batteries.
