Chemical Crossover Accelerates Degradation of Lithium Electrode in High Energy Density Rechargeable Lithium-Oxygen Batteries
Chemical Crossover Accelerates Degradation of Lithium Electrode in High Energy Density Rechargeable Lithium-Oxygen Batteries
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DOI：
10.1002/aenm.202203062
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发表时间：
2023-01-30
影响因子：
27.8
通讯作者：
Uosaki, Kohei
中科院分区：
文献类型：
--
作者：
Matsuda, Shoichi;Ono, Manai;Uosaki, Kohei
锂氧电池(LOB)因其理论能量密度超过传统锂离子电池而成为下一代可充电电池的候选电池。虽然在贫电解液和高面容量条件下已经证明了具有高电池能级能量密度的LOB，但它们的循环寿命仍然很差，电池的降解机理尚不清楚。在本研究中，利用三电极电化学装置和现场MS分析技术，发现锂负极的反应效率大大降低，这是由于正氧电极侧的化学交叉，如H2O和CO2。基于这种机理认识，制作了一种具有超轻质柔性陶瓷基固相分离器的LOB，其厚度为6微米，在不降低LOB能量密度的情况下有效地保护了锂电极的化学交叉。值得注意的是，400Wh kg(-1)级LOB在>；20个循环中表现出稳定的放电/充电过程。这项研究中展示的策略为高能量密度和长循环寿命的LOB的实际实施指明了方向。
Lithium-oxygen batteries (LOBs) are promising next-generation rechargeable battery candidates due to theoretical energy densities that exceed those of conventional lithium-ion batteries. Although LOB with high cell level energy density has been demonstrated under lean electrolyte and high areal capacity conditions, their cycle life is still poor, and the cell degradation mechanism remains unclear. In the present study, by use of a three-electrode electrochemical setup and in situ MS analytical techniques, it is revealed that the reaction efficiency of the negative lithium electrode largely decreases due to chemical crossover from the positive oxygen electrode side, such as H2O and CO2. Based on this mechanistic understanding, a LOB with an ultra-lightweight flexible ceramic-based solid-state separator with 6 mu m thickness that effectively protects the lithium electrode against chemical crossover without diminishing the energy density of LOBs is fabricated. Notably, a 400 Wh kg(-1) class LOB exhibits a stable discharge/charged process for >20 cycles. The strategy demonstrated in this study sheds light on the direction for the practical implementation of LOBs with high energy densities and long cycle lives.