Abstract
2H phase molybdenum disulfide(2H-MoS2)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 mech-anism.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 pulveriza-tion of coarse Mo NPs through surface sulfurization and accompanying lithiation.To overcome the insta-bility issue,proper modifiers should be introduced to restrain the spontaneous growth of Mo NPs,such as aluminum oxide(Al2O3).The strong Mo-Al2O3 bond gradually"drags"Al2O3 fragments into the active material as the cycle continuously proceeds,resulting in the efficient refinement and the reversible con-version between Mo and MoS2.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.
基金项目
Beijing Municipal Great Wall Scholar Training Plan Project(CIT&TCD20190307)
北京市教委项目(KZ202210005003)
国家自然科学基金(51621003)
国家自然科学基金(U1607110)
国家自然科学基金(12074017)
Beijing Hundred,Thousand and Ten Thousand Talent Project(2020016)
Beijing municipal High-level innovative team building program(IDHT20190503)
NETL
NSTL
万方数据