Biobinder Nanocoating for Upgrading the Assembling Structures of High-Capacity Composite Electrodes with a Robust Polymeric Artificial Solid Electrolyte Interphase

Abstract

The success of next-generation lithium-ion batteries (LIBs) fundamentally depends on the rational design of not only the microstructure of an individual component but the component assembling structures on the electrode level. However, building advanced assembling structures for especially high-capacity electrodes is an urgent but a challenging task due to the lacking of in-depth understanding and effective strategies. Here, we propose a functional nanocoating biobinder using the well-known poly­(lactic acid) to address the above need. It is found that the composite electrodes with this nanocoating biobinder are upgraded with uniform and robust assembling structures, including the electron-transportation network, ion-transportation network, and interfaces. Importantly, the nanocoating finally works as a new type of polymeric artificial cathode electrolyte interphase (poly-CEI) to protect the active particles. Therefore, a remarkable improvement in the electrochemical performance has been achieved for high-capacity electrodes (LiFePO4, lithium nickel cobalt manganite (NCM), and lithium nickel cobalt aluminum acid (NCA)). In particular, the LFP cathode can deliver a high discharge capacity of 74.6 mA h g–1 at 10C and a high capacity retention of 95.5% even after 850 cycles at 2C. For NCA and NCM cathodes, the cycling stability is dramatically improved due to the protection by the poly-CEI. In short, this study may reshape the essential roles of a binder in composite electrodes by highlighting its critical link to assembling structures.

Mn2+ Ions Capture and Uniform Composite Electrodes with PEI Aqueous Binder for Advanced LiMn2O4-Based Battery

“…In contrast, the LMO cathode prepared by PVDF-NMP binder system exhibit obviously different composite structures in Figure g,h. Big active particles barely covered by binder can be found on the top surface due to the strong crystallization and insufficient interaction of PVDF, , while many electrode components settle on the bottom to form a dense structure. The difference in composition is further revealed by the EDS mapping (Figure e,f).…”

“…And it is widely known that binder plays an important role in the electrode fabrication process, which greatly affects the materials interface structure, electron and ion transportation, and components distribution of the final cured electrode . The traditional cathode processing is based on polyvinylidene fluoride/ N -methyl-2-pyrrolidone (PVDF/NMP) system, which have long been blamed for toxic mutagenic materials, insufficient binding force, and high raw material costs. − In particular, the slow drying of NMP may lead to uneven stacking and gradient distribution of cathode materials during the long drying time, which exert adverse effects on the electron and ion transportation, interfacial structure, and interactions. In this paper, we use water as solvent when preparing PEI-based electrodes.…”

Constructing Low‐Impedance Li7La3Zr2O12‐Based Composite Cathode Interface for All‐Solid‐State Lithium Batteries

“…As an important auxiliary functional material inside the composite cathode of ASSLBs, the binder is a polymer compound that adheres to other composite cathode components, for example, active materials, to enhance the contact between particles of CAMs and conductive agents and stabilize the structure, which is an additional material with high technical content in battery materials. [ 65 ] Research shows that although the amount of binder in the electrode sheet is relatively small, the performance of the binder directly affects the capacity, life, and safety of ASSLBs. [ 66 ]…”

High‐Performance Flexible Sulfur Cathodes with Robust Electrode Skeletons Built by a Hierarchical Self‐Assembling Slurry

“…However, the high‐level structures of composite electrodes formed from all the components, denoted as assembly structures, are another key factor controlling the ion and electron transport capabilities of these electrodes, as well as their structural stability during cycling. [ 9 , 10 ] Assembly structures are physically similar to the quaternary structures well known in protein science, which are significant for facilitating their biological functionality. Therefore, efforts to address the limitations of Li–S batteries require the development of strategies for realizing well‐designed and controlled assembly structures in composite sulfur electrodes.…”