Zhang Shuo, Yan Chong, Xiao Ye, Wu Yi-Hui, Huang Jia-Qi
School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, China.
Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, 100081, China.
Adv Mater. 2025 Jul;37(26):e2503582. doi: 10.1002/adma.202503582. Epub 2025 Apr 29.
Anode-free lithium metal battery (AFLMB) has become an excellent candidate for long endurance electric vehicles and electric low altitude aircraft, profiting from its high energy density as well as outstanding manufacturing safety. However, the limitation at high discharge rates of AFLMBs is shrouded in mystery, yet to achieve more attention. Herein, the limitation of fast discharge for AFLMBs is dissected exhaustively, and a symptomatic strategy to break the limit is put forward, in order to eliminate the inevitable mismatch that lies in the inferior performance of AFLMBs. A "volcano-type" curve of capacity retention of AFLMBs is discovered with the discharge rate increased. Systematic investigation revealed that the overlapped spatial relationship between fresh deposited Li and residue Li facilitated the utilization of "recoverable Li" (Li) at the prophase of discharge rate increase. However, further enhanced discharge rate induced large concentration polarization (η), reflecting limited Li diffusion. Enabling the electrolyte to rapidly transport Li by lowering η increased the optimal discharge rate as well as the cycling stability of AFLMBs. This work reveals the rate-determining step for high-rate discharge and expands the employment boundary of AFLMBs under harsh conditions, providing a significant complement of present knowledge with respect to the power performance of AFLMBs.
无阳极锂金属电池（AFLMB）因其高能量密度以及出色的制造安全性，已成为长续航电动汽车和电动低空飞行器的理想选择。然而，AFLMB在高放电率下的局限性仍不明朗，尚未得到更多关注。在此，对AFLMB快速放电的局限性进行了详尽剖析，并提出了突破该限制的对症策略，以消除AFLMB性能不佳中不可避免的不匹配问题。随着放电率增加，发现了AFLMB容量保持率的“火山型”曲线。系统研究表明，新沉积的锂与残留锂之间重叠的空间关系有助于在放电率增加的前期利用“可回收锂”（Li）。然而，进一步提高放电率会导致较大的浓差极化（η），反映出锂扩散受限。通过降低η使电解质快速传输锂，提高了AFLMB的最佳放电率以及循环稳定性。这项工作揭示了高倍率放电的速率决定步骤，并扩展了AFLMB在苛刻条件下的应用边界，为当前关于AFLMB功率性能的知识提供了重要补充。
