The first mass-produced electric vehicle (EV) with semi-solid battery tech is coming in 2025. The Chinese automaker SAIC unveiled the second generation of its MG4, a compact hatchback popular in both China and the UK. It delivers a range of 537 km and pack-level specific energy of 180 Wh/kg – surpassing the BYD Blade. What is remarkable is the use of a legacy chemistry, lithium manganate (LMO), in surpassing the performance and cost of lithium-iron-phosphate (LFP). Could we be on the brink of the renaissance of an old chemistry, echoing LFP’s comeback in 2020?
Semi-solid will threaten demand for all-solid-state batteries
All-solid-state batteries (ASSBs) are often touted as the “holy grail” technology as they promise rapid charging speeds, super-long EV ranges and high safety all in one. However, developers have yet to overcome challenges in ASSB cycle life (how many times a battery can be charged/discharged before its capacity plummets).
The poor cycle life arises from solid-solid interfaces breaking apart during use with no liquid to fill the gaps, resulting in lost capacity. Producers have turned to using high pressure clamps to maintain interface contact, but this adds too much weight and volume to warrant adoption.
Semi-solid batteries (SSBs) are a compromise technology that could render ASSBs redundant. SSBs are similar to ASSBs but retain some liquid content. The added weight is a trade-off, but it substantially increases the cycle life and improved performance on current liquid electrolyte cells. We see SSBs performance as good enough for most EV segments, pushing ASSBs to the very premium vehicles or ultra-long ranges – if it eventually reaches mass production.
SAIC’s semi-solid pack will contain cells from startup Qingtao Energy and announced use of a manganese-based chemistry, with very few other details. The SAIC-Qingtao joint venture has published three patents relating to semi-solid battery technologies, focused on halide solid-electrolytes combined with a polymer gel or liquid electrolyte.
The choice of cathode material is far more interesting. We believe that Qingtao’s first-generation semi-solid battery contains lithium-nickel-manganese-cobalt-oxide cathodes (NMC), but its second-generation cell – those equipped in SAIC vehicles – will utilise a high-voltage manganese cathode.
Indeed, Qingtao Energy has filed patents specifying both lithium manganate (LMO) or lithium-nickel-manganese-oxide (LNMO) cathode materials, as well as inclusion of a lithium supplement material (e.g. Li2O2) in the cathode layer. The use of LMO could displace the use of LFP cells, and semi-solid LNMO could be the last nail in the coffin for NMC in China.
LMO could make a comeback
The industry has already witnessed one renaissance of a legacy chemistry. LFP was the preferred chemistry in China in the early 2010s due to its low cost, but its market share fell as NMC was preferred for EV range. However, material development and cell-to-pack innovation in China resulted in LFP’s comeback and current dominance in today’s market.
LMO’s story is not dissimilar. Early EVs used the LMO chemistry due to its power capability, but improvements in NMC led to displacement of LMO market share. LMO’s low capacity makes it more expensive and a worse overall performer.
However, semi-solid battery technology could enable the comeback of LMO. By adding a lithium supplement on the cathode, Qingtao could raise the capacity of LMO and LNMO to 150–170 mAh/g, in-line with LFP, and improved cell safety by using a solid-electrolyte.
Furthermore, the high power of LMO and LNMO could enable ultra-thick cathodes of 200μm, double that of typical electrodes. This vastly reduces the amount of passive material, including costly solid-electrolyte, in a cell. Combined with a high cell voltage, Qingtao’s Gen2 cells could rival NMC in specific energy and LFP in cost with sufficient scale of solid electrolyte production.
However, even with the lithium supplement, semi-solid cells cannot compete with NMC on energy density at a cell level. SAIC will need to introduce cell-to-pack architecture to overcome the shortfall in cell energy density to maintain the same EV range as an NMC pack.
A usual concern is price. We expect Qingtao’s semi-solid costs – based on scaled production volumes – to be much higher than current technologies due to high solid-electrolyte costs. However, surging demand will reduce unit costs and, if companies successfully scale solid-electrolyte production to hundreds of gigawatt-hours scale, SSBs would have a seismic impact on the industry.
According to its website, Qingtao Energy is currently operating 2 GWh capacity for Gen2 cells with a further 25.5 GWh under construction. Meaningful adoption of its semi-solid batteries in 2026 will incentivise new production capacity, and at China’s rapid construction time this could result in several hundred GWh of production by 2030, still small compared to the over 1 TWh of EV demand in China in 2030.
However, LFP rose to dominance in under five years through rapid deployment of capacity across many companies. WeLion, Ganfeng, SVOLT and other Chinese companies have already committed to semi-solid battery production. China has the ability to start another upheaval in the battery chemistry mix.
A semi-solid supply chain is needed for meaningful impact
Adoption of semi-solid battery technology aligns with China’s cell engineering philosophy, which has been to incrementally optimise incumbent technologies rather than try to leapfrog them with a breakthrough.
The impact would be significant for Europe, whose automakers are eager to buy low-cost and high-performance batteries. Fast-charging LFP and long-range semi-solid would cover the needs of automakers’ portfolios, both well-served by Chinese cellmakers. The trend in use of Chinese batteries in European EVs will strengthen, to the detriment of European cellmakers. South Korean cellmakers will at least be shielded in the US market, due to the prohibitive tariff regime established under President Trump’s administration.
Displacement of NMC chemistries would cut demand for nickel and cobalt, while the success of LNMO would dampen lithium demand. Despite introducing a lithium rich supplement in the semi-solid cathode, the improvement in energy density and lower lithium content in LNMO results in an overall decline in lithium intensity.
If Qingtao’s semi-solid battery technology takes off, battery supply chains would continue to concentrate in China – whose LMO or LNMO cathode and proprietary semi-solid cell production techniques will be protected by the Chinese government through measures on technology export regulation outside its borders.
However, there are many hurdles to the success of semi-solid batteries and manganese-rich cathodes. The use of Li2O2 creates issues with gas evolution which needs to be supressed. Using ultra-thick electrodes will also require careful manufacturing to sustain conductivity. Significant investment has already been made in LFP cathode production, which would need retrofitting to make up for lacking capacity for the legacy manganese-rich chemistries.
Semi-solid is still unproven at scale. Ganfeng Lithium and WeLion first tested semi-solid batteries in EVs in 2023, with slow movement since then. Qingtao Energy’s use of its semi-solid tech in the MG4 is likely to be limited to under 10,000 vehicles in its first year, and it faces a long road to competitive cell costs given the significant price reduction required in its electrolyte material.
SSB production uses many of the same equipment in current gigafactories, and cellmakers can adapt production lines in a matter of months. The performance improvement on current cells and potential low-cost production gives semi-solid batteries a profound appeal to automakers.
The battery market is extremely challenging to predict, but if other cellmakers seriously consider manganese-based chemistries in their portfolios, LMO could be the next LFP. Semi-solid seems the more likely “holy grail” technology and will become commonplace in automakers’ strategies. ASSBs, with all their complications, will remain an excessive technology for what is generally needed, and so will see uptake limited to niche applications.
To learn more about battery technology developments and their impact on cell costs, please get in touch regarding CRU’s Battery Technology and Cost Model.
