Dr Ceren Zor and Dr Stephen J Turrell explain, in this paper* published in Advanced Energy & Sustainability Research that Li-ion batteries (LIBs) have been widely used in portable electronic devices, the transportation sector and in grid storage, however they are restricted to carbon-based materials limiting their energy density.
Recently, the use of metallic Li as the anode in Li-metal (LMBs) and solid-state (LMBSSs) batteries has gained attention due to the high energy densities it can provide. In this paper, the research progress in the field to derive a broad picture of the technologies relying on Li metal as the anode is critically assessed.
It is essential to understand the Li plating and stripping processes in terms of fundamental electrochemical and physical mechanisms to address the challenges of employing metallic Li. Anode-free Li-metal batteries (AFLMBs) and anode-free solid-state batteries (AFSSBs) are the most attractive systems discussed in this review.
AFLMBs are highly studied, but safety concerns due to Li dendrite growth and side reactions between plated Li metal and liquid electrolyte are some key challenges yet to be resolved. AFSSBs are the ultimate goal in this field, as utilising a solid-state electrolyte (SSE) can prevent dendrites at moderate charging rate and realise the potential of the anode-free battery. The general problems with the use of SSEs, however, remain and require substantial research efforts.
*'Lithium plating and stripping: toward anode-free solid-state batteries'.