Gao Panyu, Ju Shunlong, Xu Tian, Du Wubin, Gao Yong, Yang Yaxiong, Li Zhenglong, Zhang Hongyu, Huang Yuqin, Xia Guanglin, Wang Fei, Yu Xuebin
College of Smart Materials and Future Energy, Fudan University, Shanghai, 200433, China.
Institute of Science and Technology for New Energy, Xi'an Technological University, Xi'an, 710021, China.
Adv Mater. 2025 Jul 20:e08008. doi: 10.1002/adma.202508008.
The practical application of LiBH in all-solid-state Li metal batteries (ASSLMBs) is hindered by low Li-ion conductivity at room temperature, poor oxidative stability, and severe dendrite growth. Herein, porous [LiNBH] with a hydrogen-deficient chain-like molecular structure are designed for in situ space-confining LiBH, which enables strong attraction of negatively charged H atoms of [BH] anions by Li of [LiNBH] chains that weakens Coulombic interaction between Li and [BH] anions and hence promotes Li ion diffusion. Additionally, the electron-withdrawing effect of [LiNBH] chains induces the local electron localization of LiBH that enhances oxidative stability of LiBH. Therefore, the Li ion conductivity of LiBH reaches 2.2 × 10 S cm at 30 °C, nearly 4 orders of magnitude higher than that of LiBH, with a voltage window of 5 V. Moreover, the interaction between Li metal and [LiNBH] chains results in in situ formation of ultrathin layer composed of LiN and LiB alloys that hinders Li dendrites growth, leading to a critical current density value of 7.5 mA cm and a cycling life of 100 h at 4 mA cm with an overpotential of 125 mV. Hence, LiCoO|LiBH-70LiNBH|Li cell at 0.5 C deliver a high capacity of 89.5 mA h g after 400 cycles.
LiBH在全固态锂金属电池（ASSLMBs）中的实际应用受到室温下锂离子电导率低、氧化稳定性差和严重枝晶生长的阻碍。在此，设计了具有缺氢链状分子结构的多孔[LiNBH]用于原位空间限制LiBH，这使得[LiNBH]链中的Li能够强烈吸引[BH]阴离子带负电的H原子，从而削弱Li与[BH]阴离子之间的库仑相互作用，进而促进锂离子扩散。此外，[LiNBH]链的吸电子效应诱导了LiBH的局部电子定位，增强了LiBH的氧化稳定性。因此，LiBH在30℃时的锂离子电导率达到2.2×10 S cm，比LiBH高出近4个数量级，电压窗口为5 V。此外，锂金属与[LiNBH]链之间的相互作用导致原位形成由LiN和LiB合金组成的超薄层，阻碍了锂枝晶的生长，在4 mA cm下临界电流密度值为7.5 mA cm，循环寿命为100 h，过电位为125 mV。因此，LiCoO|LiBH-70LiNBH|Li电池在0.5 C下400次循环后可提供89.5 mA h g的高容量。
