Toward rechargeable lithium–oxygen batteries: recent advances

Abstract

This review summarizes research and development trends in lithium-oxygen (Li-O 2 ) batteries. Development of a post-lithium-ion battery is highly expected to be a means to solve the global energy problem. The metal-oxygen cell, especially the Li-O 2 cell, attracts attention, since it has much larger theoretical energy density than conventional battery systems. First, this review discusses the energy density that a battery should have from the viewpoint of power sources for electric vehicles. Then the fundamental features of various kinds of metal-oxygen batteries are explained and challenges faced by them are described. The remaining part of the review focuses on research subjects of the Li-O 2 batteries. Early works which led to the present lithium-oxygen cells are briefly presented. Then, systems using various electrolytes and their major issues are introduced. First, irreversible decomposition of the electrolyte and Li 2 O 2 deposition at oxygen cathode of an organic system are described. The effort that is directed toward the solution of dendritic growth of lithium metal anode is also introduced. Thereafter, new materials, mechanisms, and strategy that were reported recently are described with regard to each of the three electrolyte systems, respectively. These are expected to be breakthroughs to solve the serious problems, such as irreversible decomposition of electrolyte. In conclusion, the issues that should be solved with the direction of future development are mentioned.

Methods for Lithium Ion NASICON Preparation: From Solid-State Synthesis to Highly Conductive Glass-Ceramics

“…Partial reduction of Ti 4+ into Ti 3+ culminates in electronic conduction, reducing the ionic transference number . Furthermore, the Ti 4+ /Ti 3+ reduction at a relatively low potential (1.6 V vs Li + /Li) also makes this material unstable in contact with metallic lithium electrodes. ,, Therefore, glass-ceramics with a Li 1+ x Al x ­Ge 2– x (PO 4 ) 3 composition emerge as an alternative to the former. They approach conductivities in the same order (10 –4 to 10 –3 S cm –1 ) ,,,, and present lower melting temperature for the raw oxides and greater stability against a lithium electrode …”

“…There are several possibilities for the cells’ construction, and different testing conditions are required by consequence. Some storage technologies use NASICON as an interlayer between the electrode and liquid electrolyte, since they successively block the reaction of these components by impeding their direct contact. , Several devices require the stability of NASICON in contact with water or aqueous solutions. ,, A considerable amount of research about NASICON glass-ceramics is, therefore, aimed at understanding their stability when in contact with different types of electrodes and aqueous and aprotic electrolytes. ,,,− As examples, some studies have evaluated the production of cathode thin films such as LiCo 1– x B x O 2 (B = Mn, Ni) on the NASICON glass-ceramics. ,− There are reports focusing on the interface and degradation of NASICON with lithium electrode and liquid electrolytes. , The latter material demonstrated to be stable in a neutral medium but reactive in acid and basic electrolytes. Surface reactions occurring in acids caused a decrease in conductivity as a function of time, which is harmful for practical applications. ,, …”

“…To develop environmentally safe electrical vehicles and grid storage technologies, stable batteries with safe operation and high specific capacity are required. − Specifically, lithium ion batteries present the highest energy density and open-circuit voltage currently applied on a large scale. − Moreover, lithium is relatively inexpensive, light, and electropositive, and it has a large reduction potential (−3.024 V vs standard hydrogen electrode) . High output voltage in current devices is obtained, , as a huge theoretical capacity for oncoming technologies such as lithium–air batteries. − …”

“…10−12 Moreover, lithium is relatively inexpensive, light, and electropositive, and it has a large reduction potential (−3.024 V vs standard hydrogen electrode). 13 High output voltage in current devices is obtained, 14,15 as a huge theoretical capacity for oncoming technologies such as lithium−air batteries. 15−17 Traditional Li + -batteries comprise a liquid electrolyte, based on a solution of lithium salts dissolved in organic solvents.…”