2021, Jiang, Guangshen, Qu, Changzhen, Xu, Fei, Zhang, En, Lu, Qiongqiong, Cai, Xiaoru, Hausdorf, Steffen, Wang, Hongqiang, Kaskel, Stefan

Enhancing ionic conductivity of quasi-solid-state electrolytes (QSSEs) is one of the top priorities, while conventional metal–organic frameworks (MOFs) severely impede ion migration due to their abundant grain boundaries. Herein, ZIF-4 glass, a subset of MOFs, is reported as QSSEs (LGZ) for lithium-metal batteries. With lean Li content (0.12 wt%) and solvent amount (19.4 wt%), LGZ can achieve a remarkable ion conductivity of 1.61 × 10−4 S cm−1 at 30 °C, higher than those of crystalline ZIF-4-based QSSEs (LCZ, 8.21 × 10−5 S cm−1) and the reported QSSEs containing high Li contents (0.32–5.4 wt%) and huge plasticizer (30–70 wt%). Even at −56.6 °C, LGZ can still deliver a conductivity of 5.96 × 10−6 S cm−1 (vs 4.51 × 10−7 S cm−1 for LCZ). Owing to the grain boundary-free and isotropic properties of glassy ZIF-4, the facilitated ion conduction enables a homogeneous ion flux, suppressing Li dendrites. When paired with LiFePO4 cathode, LGZ cell demonstrates a prominent cycling capacity of 101 mAh g−1 for 500 cycles at 1 C with the near-utility retention, outperforming LCZ (30.7 mAh g−1) and the explored MOF-/covalent–organic frameworks (COF)-based QSSEs. Hence, MOF glasses will be a potential platform for practical quasi-solid-state batteries in the future. © 2021 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH

2022, Xu, Fei, Qu, Changzhen, Lu, Qiongqiong, Meng, Jiashen, Zhang, Xiuhai, Xu, Xiaosa, Qiu, Yuqian, Ding, Baichuan, Yang, Jiaying, Cao, Fengren, Yang, Penghui, Jiang, Guangshen, Kaskel, Stefan, Ma, Jingyuan, Li, Liang, Zhang, Xingcai, Wang, Hongqiang

Constructing robust nucleation sites with an ultrafine size in a confined environment is essential toward simultaneously achieving superior utilization, high capacity, and long-term durability in Na metal-based energy storage, yet remains largely unexplored. Here, we report a previously unexplored design of spatially confined atomic Sn in hollow carbon spheres for homogeneous nucleation and dendrite-free growth. The designed architecture maximizes Sn utilization, prevents agglomeration, mitigates volume variation, and allows complete alloying-dealloying with high-affinity Sn as persistent nucleation sites, contrary to conventional spatially exposed large-size ones without dealloying. Thus, conformal deposition is achieved, rendering an exceptional capacity of 16 mAh cm−2 in half-cells and long cycling over 7000 hours in symmetric cells. Moreover, the well-known paradox is surmounted, delivering record-high Na utilization (e.g., 85%) and large capacity (e.g., 8 mAh cm−2) while maintaining extraordinary durability over 5000 hours, representing an important breakthrough for stabilizing Na anode.