无铅钙钛矿储能器件中PVDF-Li⁺离子界面化学的普适性
An Interfacial Balance Rule Governs Binder-Electrolyte Coupling in Lead-Free Perovskite Energy Storage
- Indian Institute of Technology Roorkee（印度理工学院鲁尔基分校）
- SR University（SR大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
该研究发现无铅钙钛矿超级电容器中PVDF粘结剂与Li⁺的界面化学具普适性，提出界面平衡规则，揭示PVDF平面构型调控锂吸附的机制，表明粘结剂负载是储能界面的活性设计参数。
AI中文摘要：
电极粘结剂通常被视为惰性结构组分。本文表明，在无铅钙钛矿超级电容器中，粘结剂决定了最优电解质组成。在CsSnCl₃电极中聚偏二氟乙烯（PVDF）负载量与双三氟甲磺酰亚胺锂（LiTFSI）浓度的因子矩阵中，电容最优值随粘结剂含量沿单一线性关系系统偏移，该关系由界面平衡规则（λ+θ=1）描述，其中λ和θ为优化界面态下归一化的锂供给与聚合物贡献。该关系对混合MASnCl₃同样成立，表明最优值由聚合物-电解质界面而非钙钛矿晶格化学决定。使用预训练的MACE机器学习原子间势的模拟显示，PVDF在CsSnCl₃上采用平面构型，同时与阳离子和阴离子位点相互作用。该构型使锂吸附能量均匀化，引入氟介导的配位，将锂限制在二维界面区域同时保持横向迁移性。通过表面密度和链长调节聚合物覆盖度，揭示了有限的界面锂容纳容量，这标志着平面外聚集的开始。界面平衡规则为该有限界面资源提供了宏观描述符，平衡了聚合物介导的锂稳定与有限容纳空间。因此，粘结剂负载是聚合物调控储能界面的活性设计参数。
英文摘要：
Electrode binders are conventionally regarded as inert structural components. Here, we show that in lead-free perovskite supercapacitors, the binder defines the optimal electrolyte composition. Across a factorial matrix of poly(vinylidene fluoride) (PVDF) loadings and LiTFSI concentrations in CsSnCl$_3$ electrodes, the capacitance optimum shifts systematically with binder content along a single linear relationship, described by the Interfacial Balance Rule ($λ+θ=1$), where $λ$ and $θ$ are the normalized lithium-supply and polymer contributions at the optimized interfacial state. The same relationship holds for hybrid MASnCl$_3$, showing that the optimum is governed by the polymer-electrolyte interface rather than the perovskite lattice chemistry. Simulations using a pre-trained MACE machine-learned interatomic potential show that PVDF adopts a planar configuration on CsSnCl$_3$ and simultaneously interacts with cationic and anionic sites. This configuration homogenizes lithium adsorption energetics, introduces fluorine-mediated coordination, and confines lithium to a two-dimensional interfacial region while preserving lateral mobility. Tuning polymer coverage through surface density and chain length reveals a finite interfacial lithium accommodation capacity that marks the onset of out-of-plane aggregation. The Interfacial Balance Rule provides a macroscopic descriptor of this finite interfacial resource, balancing polymer-mediated lithium stabilization against limited accommodation space. Binder loading is therefore an active design parameter for polymer-regulated energy-storage interfaces.
