Dong Wujie, Huang Xieyi, Jin Yan, Xie Miao, Zhao Wei, Huang Fuqiang
State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, P. R. China.
Dalton Trans. 2020 Jun 23;49(24):8136-8142. doi: 10.1039/d0dt00901f.
Spinel lithium manganate (LiMn2O4) is a promising cathode for aqueous lithium-ion batteries (ALIBs). However, due to Mn dissolution and the Jahn-Teller effect it suffers from fast capacity fading, insufficient rate capability, and low overcharge resistance. Herein, a ∼2-3 nm artificial solid electrolyte interphase (SEI) layer (lithium polyacrylate, LiPAA) is constructed on the commercial LiMn2O4 (LiPAA@LiMn2O4). It is realized by an in situ polymerization hydrothermal reaction using an acrylic monomer. This artificial SEI layer can separate the electrode and aqueous electrolyte, thus suppressing Mn dissolution and the Jahn-Teller effect of LiMn2O4. Electrochemical analyses also suggest it may work as the Li+ conductor/reservoir to improve the Li+ diffusion coefficient of the electrode. Consequently, as the cathode of ALIBs, LiPAA@LiMn2O4 harvests a high capacity of 119 mA h g-1 at 0.6C, high rate capability (70 mA h g-1 at 12C), better durability (85.5%@100 cycles) and superior overcharge resistance.
尖晶石型锰酸锂（LiMn2O4）是水系锂离子电池（ALIBs）中一种很有前景的正极材料。然而，由于锰溶解和 Jahn - Teller 效应，它存在容量快速衰减、倍率性能不足和过充耐受性低等问题。在此，在商用 LiMn2O4（LiPAA@LiMn2O4）上构建了一层约 2 - 3 纳米的人工固体电解质界面（SEI）层（聚丙烯酸锂，LiPAA）。这是通过使用丙烯酸单体的原位聚合水热反应实现的。这种人工 SEI 层可以将电极与水系电解质隔开，从而抑制 LiMn2O4 的锰溶解和 Jahn - Teller 效应。电化学分析还表明它可以作为 Li + 导体/储库来提高电极的 Li + 扩散系数。因此，作为 ALIBs 的正极，LiPAA@LiMn2O4 在 0.6C 时具有 119 mA h g-1 的高容量、高倍率性能（12C 时为 70 mA h g-1）、更好的耐久性（100 次循环后为 85.5%）和优异的过充耐受性。
