Xia Shuhui, Zhao Yun, Yan Jianhua, Yu Jianyong, Ding Bin
Key Laboratory of Textile Science and Technology, College of Textile, Donghua University, Shanghai 201620, China.
Innovation Center for Textile Science and Technology, Donghua University, Shanghai 200051, China.
ACS Nano. 2021 Feb 23;15(2):3161-3170. doi: 10.1021/acsnano.0c09745. Epub 2021 Jan 26.
Lithium (Li) metal batteries (LMBs) offer great opportunity for developing high-energy density energy-storage-systems, but the anodes suffer a severe problem of dendrite growth that hinders the practical applications of LMBs. Here, we report a soft BaTiO ceramic nanofiber film with excellent ferroelectricity and piezoelectricity that enables one to transverse the dense deposition of Li metal. During Li plating, the strong ferroelectricity reduces the Li-ion concentration gradient near the anode and thus facilitating their uniform deposition. Once squeezed by these Li deposits, the BaTiO film generates instantaneous piezo-effect to dynamically change the subsequent Li deposition from vertical to lateral. As a result, Li-Cu cells exhibit reversible plating-stripping processes for over 200 cycles with a high Coulombic efficiency of >98.3%. When pairing with high-voltage LiNiCoAlO cathodes, the LMBs can retain >80% capacity in 300 cycles without forming dendrites even under challenging conditions including a high cathode loading of 7.2 mg/cm, a lean electrolyte amount of 7 μL/mg, and high current rates. The findings point to a promising electromechanical coupling strategy to dynamically adjust dendrite growth for designing Li metal anodes.
锂（Li）金属电池（LMBs）为开发高能量密度储能系统提供了巨大机遇，但阳极存在严重的枝晶生长问题，这阻碍了LMBs的实际应用。在此，我们报道了一种具有优异铁电性和压电性的柔软钛酸钡（BaTiO）陶瓷纳米纤维膜，它能够实现锂金属的致密沉积。在锂电镀过程中，强大的铁电性降低了阳极附近的锂离子浓度梯度，从而促进其均匀沉积。一旦被这些锂沉积物挤压，BaTiO膜会产生瞬时压电效应，将随后的锂沉积从垂直方向动态改变为横向方向。结果，锂 - 铜电池在超过200次循环中表现出可逆的电镀 - 剥离过程，库仑效率高达>98.3%。当与高压锂镍钴铝氧化物（LiNiCoAlO）阴极配对时，即使在具有挑战性的条件下，包括阴极高负载7.2 mg/cm²、贫电解液量7 μL/mg和高电流速率，LMBs在300次循环中仍能保持>80%的容量且不形成枝晶。这些发现指出了一种有前景的机电耦合策略，用于动态调节枝晶生长以设计锂金属阳极。
