Pengfei Yan1 Jianming Zheng2 Jian Liu3 Xueliang Sun3 Chongmin Wang1 Ji-Guang Zhang1

1, Pacific Northwest National Laboratory, Richland, Washington, United States
2, Pacific Northwest National Laboratory, Richland, Washington, United States
3, University of Western Ontario, London, Ontario, Canada

In this work, we report a new approach to enhance the cycle stability of aggregated cathode particles for lithium ion battery at both room and elevated temperatures. We discover that infusion of a solid electrolyte into the grain boundaries of the cathode secondary particles can dramatically enhance the capacity retention and voltage stability of the battery. We find that the solid electrolyte infused in the boundaries not only acts as a fast channel for Li ion transport, but also most importantly prevents penetration of the liquid electrolyte into the boundaries, consequently eliminating the detrimental factors that include solid-liquid interfacial reaction, intergranular cracking, and layer to spinel phase transformation. The present work, for the first time, reveals unprecedented insight as how the cathode behaves in the case of not contacting with the liquid electrolyte, ultimately points toward a general new route, via grain boundary engineering, for designing of better batteries of both solid liquid and solid state systems.