The authors report novel results toward optimizing the electrochemical performance of high vacuum deposited lithium-based all solid-state thin film microbatteries. This study investigated hermetic encapsulation, interfacial lithium formation processes, and the role of Li-blocking and Li-nucleating layers for improved Li-metal plating on copper anodes. Photoresist was found to be an effective temporary encapsulation material, where prior to cycling, well-encapsulated Li-metal full cells yielded a total resistance reduction of nearly two orders of magnitude (282 Ω cm²) and a total capacitance increase of roughly an order of magnitude (1.35 × 10⁻¹⁰ F/cm²) compared with nonencapsulated Li-metal full cells. To accelerate potential failure mechanisms, high stress applied currents were used during the electrochemical formation processes. Initial cycles caused high resistance voids to form at the lithium phosphorous oxy-nitride (LiPON)/copper interface of well-encapsulated half cells. Well-encapsulated full cells, in contrast, resulted in a very low resistance composite Li-Cu anode, with a void-free LiPON interface, two orders of magnitude lower resistance (0.43 Ω cm²) and three orders of magnitude higher capacitance (6.56 × 10⁻⁸ F/cm²) compared with the half cell. Cycling performance was investigated using both Li-blocking nickel-copper and Li-nucleating gold-copper metal bilayer anodes in 100-μm diameter half cells. Nickel-copper anodes facilitated higher discharge capacity (>9 μAh/cm²) at high charge rates (>12.7 mA/cm²) due to uniform Li-metal plating on blocking electrodes. Low charge rates (<0.7 mA/cm²) displayed low discharge capacity and immediate corrosion of the cell. Gold-copper anodes displayed the opposite effect, showing sustainable cycling, minimal cell corrosion, and a discharge capacity of >6 μAh/cm² at lower charge rates (∼0.025 mA/cm²). The work expands on fundamentals in understanding the role of the metallic anode encapsulation, interface formation, and charge storage mechanisms with respect to sustainable cell impedance for applications such as solid-state lithium metal microbatteries and microelectrochemical resistance-modulated memory devices.

中文翻译：

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固态锂金属微电池的基本原理，阻抗和性能

作者报告了有关优化高真空沉积锂基全固态薄膜微电池的电化学性能的新颖结果。这项研究调查了气密封装，界面锂的形成过程，以及锂阻隔层和锂成核层对改善铜阳极上的锂金属镀层的作用。人们发现光致抗蚀剂是一种有效的临时封装材料，在循环之前，封装良好的锂金属全电池可将总电阻降低近两个数量级（282Ωcm ²），总电容大约增加一个数量级。大小（1.35×10 ^-10  F / cm ²）与未封装的锂金属全电池相比。为了加速潜在的失效机理，在电化学形成过程中使用了高应力施加的电流。初始循环导致在良好封装的半电池的锂磷氧氮化物（LiPON）/铜界面处形成高电阻空隙。相比之下，封装良好的全电池会产生非常低电阻的复合锂铜阳极，具有无空隙的LiPON界面，低两个数量级的电阻（0.43Ωcm ²）和高三个数量级的电容（6.56） ×10 ^-8  F / cm ²）。同时使用锂阻断镍-铜和锂成核金-铜金属双层阳极的循环性能进行了调查在100- μ米直径的半格。镍-铜阳极促进更高的放电容量（> 9  μ阿/厘米²在高充电速率（>12.7毫安/厘米）²）由于均匀的Li的金属镀上阻挡电极。低充电率（<0.7 mA / cm ²）显示低放电容量并立即腐蚀电池。金-铜阳极显示了相反的效果，显示出持续循环，最小电池腐蚀，和> 6的放电容量 μ阿/厘米²在较低的充电速率（~0.025毫安/厘米²）。这项工作的基础是了解固态阳极金属微电池和微电化学电阻调制存储设备等应用中的金属阳极封装，界面形成和电荷存储机制对可持续电池阻抗的作用。