Mechanical damage of NCM811 (LiNi 0.8 Co 0.1 Mn 0.1 O 2 ), severe interfacial side reactions, and physical contact failure of cathode and solid electrolyte (SE) are the main obstacles for it to achieve high-voltage stability in all-solid-state batteries (ASSLBs). The cathode morphology effects on the structural integrity are directly related to the electrochemical performance of ASSLBs. In this work, small-size single crystal NCM811 (S-SC) is synthesized for sulfide-based ASSLBs to solve mechanical damage and contact failure issues. In addition, the interfacial stability is improved by a Li 2 O pre-lithiation strategy. Cross section polisher-scanning electron microscopy (CP-SEM) is applied to reveal the mechanical structure evolution behavior of NCM811 cathodes with different morphology. Electrochemical impedance spectroscopy (EIS), time of flight secondary ion mass spectrometry (TOF-SIMS), and X-ray photoelectron spectroscopy (XPS) technologies are applied to characterize the interfacial stability among cycling. As a result, with a high mass loading of 35.67 mg cm −2 and high current density of 7.13 mA cm −2 , the Li 2 O pre-lithiated S-SC (S-SC-PL) cathode delivers extraordinarily high-voltage stability of 100% after 500 cycles at 2.72–4.4 V and 100% after 200 cycles at 2.72–4.5 V in ASSLBs. This work provides an effective cathode morphological design strategy to improve high-voltage stability of Ni-rich layered cathodes for sulfide-based ASSLBs.
Wenjie Yuan,Jinlong Liao,Songde Huang,Dakun Song,Qinting Su,Cuihua Li,Jinhua He
Solid lithium metal batteries with solid polymer electrolytes have advantages in terms of high energy density and safety. However, their application is still hindered by unstable solid electrolyte interfaces (SEI and CEI) and uncontrolled dendrite growth. Here, a composite skeleton loaded with dielectric filler yttrium stabilized zirconia nanoparticles (YSZ) on the surface of PVDF-HFP nanofiber filaments is designed, and a novel composite solid electrolyte (CSE) is prepared by in-situ polymerization of DOL (1,3-dioxolane) on this framework to achieve safe and stable high-voltage lithium metal battery (LMB). The dual stable electrode interfaces (CEI and SEI) constructed by in-situ can effectively suppress the generation of lithium dendrites and suppress the degradation of the high-voltage NCM811 positive electrode structure and the generation of cracks in NCM811 particles, endowing the battery with extraordinary performance. The as-obtained CSE exhibits high ionic conductivity of 1.01 × 10 −3 S cm −1 at 30 °C, the enlarged electrochemical window of 6.0 V, and the Li + transference number is 0.72. The assembled Li|NCM811 battery is capable of stable cycling for 400 cycles at a cut-off voltage of 4.5 V and current density of 1C, with a capacity decay of only 0.074 % per cycle. .
Dafeng Wei,Zekai Chen,Junqiao Huang,Jinhan Li,Zhichuan Shen,Zefeng Lin,Reem Alsaigh,Nadyah Alanazi,Abdullah N. Alodhayb,Zhicong Shi
Using high-loading thick electrodes prepared by dry electrode process is an effective way for higher energy density Lithium-ion batteries(LIBs). The integration of gel polymer electrolytes (GPEs) with traditional slurry-cast thick electrodes remains fundamentally challenged by interfacial incompatibility, sluggish ion transport kinetics, mechanical stress accumulation, and parasitic side reactions from residual solvents, leading to performance decay. This study presents a novel strategy for constructing stable 4.5 V high-loading lithium-ion batteries through the synergistic integration of dry electrode and in-situ polymerized GPEs. The inherent solvent-free nature of the dry process avoids the parasitic side reactions associated with residual solvents. Consequently, the Dry electrode-LiNi 0.8 Mn 0.1 Co 0.1 O 2 (DE-NCM811) fabricated via polytetrafluoroethylene (PTFE) fibrillation-calendering demonstrates seamless interfacial compatibility when coupled with a fluorinated grafted gel polymer electrolyte formed by in-situ free-radical polymerization. Galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) evaluations confirm superior Li + diffusion kinetics and interfacial stability in the DE-NCM811|GPE|Li. Comparative electrochemical analysis reveals the superior performance of the DE-NCM811|GPE|Li, demonstrating 83.89 % capacity retention after 120 cycles in the voltage range of 3–4.5 V at 0.2 C, enhanced rate capability of 217.25 mAh g −1 at 0.1 C, stable cycling performance at high loadings of 75 mg cm −2 (80.18 % capacity retention) after 70 cycles.
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